Can We Trust Published Scientific Research?

The core principle of evidence-based medicine is that not all evidence is created equal. Controlled scientific studies provide more reliable evidence than anecdotes because they contain controls for universal sources of error in human perception and judgment. This is a major feature that distinguished science from pseudoscience, real science-based medicine from faith-based practices like homeopathy and energy medicine, in which belief and “seeing with your own eyes” always trumps controlled research evidence.

The fact that controlled research is better than haphazard observation does not, of course, mean that observation is always wrong. Nor does it mean that the results every scientific study are true. In fact, when proponents of alternative therapies try to claim that their practices actually are scientifically validated, they often parade lots of scientific studies that seem to support these claims. When the flaws in these studies that undermine their conclusions are pointed out by skeptics, this is often seen as cheating, as closed-minded rejection of evidence in favor of CAM. However, critical appraisal, the evaluation of the quality and limitations of scientific studies, is another core principle of evidence-based medicine, and it applied to all research, regardless of the kind of hypothesis under study. Scientists, unlike proponents of CAM, are generally their own toughest critics, because rigorous criticism is necessary to weed out error and eventually uncover the truth about nature.

One of the leading scientists working to identify the weakness in published scientific reports, and to develop strategies for correcting them, is John Ioannidis at Stanford University.

Ioannidis, J. Why most published research findings are false. PLoS Med 2(8): e124. doi:10.1371/journal.pmed.0020124.

Despite the inflammatory title of the article, it is actually a tightly reasoned and mathematically rigorous look at specific sources of error in the published scientific literature. Knowing the features that suggest the results of a particular article may not be reliable helps one determine the degree of confidence it is appropriate to have in a particular conclusion. Here are the features Ioannidis identifies as most significant:

  1. The smaller the studies conducted in a scientific field, the less likely the research findings are to be true.

  2. The smaller the effect sizes…

  3. The greater the number and the lesser the selection of tested relationships…

  4. The greater the flexibility in designs, definitions, outcomes, and analytical modes…

  5. The greater the financial and other interests and prejudices…

  6. The hotter a scientific field (with more scientific teams involved)…

Many of these variables are well-known to be associated with false positive results. And while they reduce our confidence in the literature of many fields, generally the CAM literature is weaker in terms of most of these factors than the literature of mainstream scientific medicine. In particular, CAM studies are seldom replicated, usually involve small numbers of patients, often show very small, marginally significant effects, and involve considerable preconceptions or bias on the part of investigators which the studies do little to control.

Many of these factors all hinge on the degree of individual judgment or flexibility allowed in a study. The more choices the investigators have to make, in the design, conduct, and analysis of a research study, the more likely their own biases are to influence the results.  Another article from a few years ago specifically addresses this issue:

Simmons JP, Nelson LD, Simonsohn U. False-positive psychology: undisclosed flexibility in data collection and analysis allows presenting anything as significant. Psychol Sci. 2011 Nov;22(11):1359-66. doi: 10.1177/0956797611417632. Epub 2011 Oct 17.

The conclusions of this paper reinforce that of Dr. Ioannidis and also emphasize a point I make here frequently; that when bias and error to creep into scientific research, they are far more likely to create the false impression of a positive result than a negative one. In other words, scientists, like all human beings, see what they want and expect to see, and if a scientific study allows these desires and expectations to influence the results, these results will tend to confirm the investigators’ beliefs even when they are false.

…flexibility in data collection, analysis, and reporting dramatically increases actual false-positive rates. In many cases, a researcher is more likely to falsely find evidence that an effect exists than to correctly find evidence that it does not.

This is, as always, true in all areas, but it is a particular problem in CAM research where investigators almost always begin with strong, nearly unshakeable faith in their beliefs and where research often has poor controls for bias generally.

The point, of course, is not to suggest that scientific studies are useless and we should all go back to believing whatever we like based on our own experiences or anecdotes told to us by others. The point is that understanding the nature and severity of the weaknesses in scientific research gives us power; power to avoid excessive confidence in our conclusions and power to correct the weaknesses that reduce this confidence.

Both Dr. Ionnidis and the authors of the article in Psychological Science offer concrete measures for improving the reliability of published research. Simmons and colleagues offer these suggestions:

These measures mostly involve more transparency in the reporting of how studies are conducted. This should both help us identify weaknesses that might reduce confidence in the results and also encourage authors to address these in the design and conduct of the trial, since they know they will have to disclose them later.

In a recent paper, Dr. Ioannidis also offers some advice for improving the quality of published scientific research:

Ioannidis JPA (2014) How to Make More Published Research True. PLoS Med 11(10): e1001747. doi:10.1371/journal.pmed.1001747

His suggestions are wide-ranging, from improved statistical practices to changing the financial and career incentives for scientists. These address both the way in which personal bias influences results and some of the sources of that bias.

Box 1. Some Research Practices that May Help Increase the Proportion of True Research Findings

  • Large-scale collaborative research

  • Adoption of replication culture

  • Registration (of studies, protocols, analysis codes, datasets, raw data, and results)

  • Sharing (of data, protocols, materials, software, and other tools)

  • Reproducibility practices

  • Containment of conflicted sponsors and authors

  • More appropriate statistical methods

  • Standardization of definitions and analyses

  • More stringent thresholds for claiming discoveries or ‘‘successes’’

  • Improvement of study design standards

  • Improvements in peer review, reporting, and dissemination of research

  • Better training of scientific workforce in methods and statistical literacy


Anything human beings do is imperfect, and this applies to science as much as anything. Often, when I suggest that science is a more reliable guide to how nature works, and what is or is not safe and effective medicine, people object that science conflicts with their personal beliefs or experiences, and they trust their gut or their eyes more than controlled data. But these sources of information contain very little in the way of controls for human error. The evidence of history, and the clear improvement in our health and well-being since we began to apply scientific methods, demonstrate that science is dramatically superior as a means for gathering knowledge than such methods.

It is true, however, that even the best methods we have for obtaining knowledge are still imperfect and still involve some freedom for bias to enter into our conclusions. Relying on science does not mean blinding trusting the results of every single study. Evidence-based medicine requires that we carefully and critically evaluate individual studies and the process of scientific research as a whole, always seeking to identify and reduce error. Merely criticizing or dismissing science as imperfect is not, in itself, useful. Such criticism must be sufficiently specific and focused to allow for strategies of improvement, and must contain at least an implicit recognition that science is still the best tool we have for understanding how nature works.



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Je Suis Charlie

Human beings are diverse. We are diverse, as individuals and as communities, in our physical characteristics and in our experiences. This leads to a diversity of beliefs and opinions. It is inevitable that we will disagree with other people about many things, large and small. And it is also inevitable that these disagreements will sometimes engender strong, often primitive and unpleasant emotions. However, it is not inevitable, and it should never be accepted or acceptable, that such disagreements lead to violence.

In his book, The Better Angels of Our Nature, Stephen Pinker makes a strong and compelling case that despite the awful things people do to one another daily around the world, and our even greater and more immediate exposure to these acts through the media, we are actually living in the safest and most peaceful time yet in human history. This is not because our biology or our fundamental nature as human beings has changed. It is because we have exercised our inherent abilities to learn, to mature, and to set limits to our own behavior. The result is often called “civilization,” and it represents a realization of at least some of the human potential to manage our feelings and our disagreements in a way that limits the damage they do and allows a measure of peace and freedom to as many people as possible.

Yesterday in Paris, there was a small, horrible, and very clear attack against civilization. Whatever the details of your beliefs, about religion or any other subject, if you have ever had a belief or opinion that you wanted to share, if you have ever disagreed with someone else’s beliefs and felt the need to say so, if you believe there is or can be such a thing as civilization, then you should feel personally attacked and personally threatened by the murder of journalists, cartoonists, police officers, and bystanders at the offices of Charlie Hebdo.

Much of the content of this blog involves criticism and critique of the claims and beliefs of others. I try to make my criticism substantive and respectful and to focus on challenging ideas and claims about the world, not attacking individuals. I do this because I believe it is necessary to give animal owners the facts and information they need to make good healthcare choices for their pets and because I feel an obligation to make a contribution to my profession and the society I live in.  While I do not wish to hurt or offend people, I understand that such critiques will inevitably be taken personally and cause offense. This, again, is in the nature of human disagreements, and it is unavoidable if we are to strive for progress and to separate good ideas from bad ideas through debate and discussion.

As a result of my writing, I have certainly received plenty of hate mail and personal verbal attacks. I have been threatened with legal action on more than one occasion in order to suppress my criticism of others. I have not yet been threatened with physical violence, though some comments have come close: “You are a lying scumbag…… eat dog shit and die !!!! you evil money monger !!!!” But in some small way, I have been involved in the attempt to sustain and contribute to civilization through civil discourse and debate, and I have been touched in a very small way by the impulses to destroy this aspect of civilization that led to the atrocity in Paris. I’m not, in any sense, as brave or important to this process as the people who lost their lives at Charlie Hebdo, but I feel a kinship and a deep respect for their commitment to civilization, which has cost them so much.

I do not read French and have not been a follower of Charlie Hebdo. From what I’ve seen in the last day, I suspect I wouldn’t like or agree with much of the satire for which the people at this magazine were attacked. But that does not lesson my belief that they had the right to produce and publish that satire, and that the attack on them is an attack on anyone who values individual freedom, freedom of belief and expression, or anything that deserves to be called civilization.

As has been said more eloquently by others before, people deserve dignity and respect, ideas do not. Even ideas people feel strongly about, such as religion, must be subject to critical evaluation, even satire, or the kind of growth and progress of civilization that has made life better for all human beings is impossible. People of all faiths and none have appropriately condemned the physical attack in Paris and the symbolic attack against freedom of thought and expression it represents.

I can think of no more appropriate way to reject this kind of barbarism and intimidation than to reproduce some of the cartoons that these attackers felt justified this kind of violence, as well as some of the responses that have been published since. If you are offended, I am sorry. But I would ask you to remember that your beliefs and opinions are just as offensive to someone else somewhere. For any one of us to have true freedom, we must defend freedom for all of us. Je suis Charlie. Nous somme tous Charlie.









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How to Pick a Vet (or How Not To)

In veterinary medicine, we have greater incentives to make our clients happy than most physicians have to satisfy their patients. Pet owners choose their vets, often on the basis of location or personal recommendation, and they can choose to find another if they aren’t happy with the care they and their pets receive. Our clients don’t experience the benefits and discomforts of our treatments directly, and they often don’t have the background or information needed to judge our competence. The veterinarian-client relationship is more about effective communication and personal rapport than it is about pet owners objectively evaluating veterinarians knowledge and skill.

On the whole, I think this is a good thing. I believe veterinarians are often better at communicating with our clients and, somewhat ironically, at the “human” side of healthcare; talking to people about their goals and fears and giving them the information they need to make important decisions. We have to be! It is still unfortunately true that veterinarians often don’t have extensive training in the communication skills that are so critical to our being able to do our jobs effectively, but as a profession I think we have the desire and the incentive to serve our clients as well as our patients as well as possible.

There is, however, a down side to the importance of subjective impressions and communication skills in establishing and maintaining relationships with pet owners. Most owners judge our manner, and how well what we say fits with their own beliefs and values, but most cannot objectively judge our competence or the accuracy of what we tell them. Therefore, clients can easily misjudge the quality of the medical care their pets are receiving.

I once worked with a doctor whose clinical practices would have been considered grossly outdated and unacceptable by the standards of almost any other veterinarian. Yet his personal charm and comforting manner immediately engendered trust and loyalty from clients. It didn’t seem to matter how his patients fared, his clients adored him even when their pets received inadequate or ineffective care and did not improve.

In contrast, I have also worked with a vet who was intelligent, compassionate, and skilled and to whose care I would have trusted my own pets without hesitation. Yet clients consistently disliked her and distrusted her recommendations due entirely to her reserved manner. It is a reality that vets are judged on how they communicate more than on the truth of what they say or the objective quality of their medicine. We must accept this and make vigorous and good faith efforts to communicate more effectively with clients so that we have the opportunity to care for our patients.

I feel, however, that it is worth warning pet owners that the reliance on somewhat superficial personal attributes in judging whether or not you have found a good vet can be misleading. A recent and stark example of this is a glowing testimonial recently posted on the web site of the American Holistic Veterinary Medical Foundation (AHVMF).

This pet owner feels she has received the best possible care for her pet, and because her pet has done well, she believes the judgment and recommendations of her vet to be correct. An evaluation of some of these recommendations informed by science, however, shows that many of these recommendations are complete nonsense, and it is very likely this patient is thriving despite rather than because of the veterinary care discussed in this testimonial.

The case was a new puppy with, according to the anecdote, skin and ear infections and intestinal parasites. The first warning sign is the blame given to vaccination for the skin and ear problems.

Our doctor suspected that the rash was most likely an allergic reaction to the vaccinations he had received from the breeder so…we began working to bolster Ceelo’s immune system.

While acute hypersensitivity reactions do occur in response to vaccination, the limited information here does not suggest that was what this pet was experiencing. Vaccine reactions are quite rare and quite distinctive, and the mistrust of vaccines induced by incorrectly blaming them for unrelated medical problems does real harm.(some facts about veterinary vaccines) And if this were a case of a vaccine reaction, it would represent an inappropriate and excessive immune system response, so the notion of “boosting” the immune system is not only nonsense, it is exactly the opposite of what ought to be done.

Things go from bad to worse as the testimonial describes the use of “various supplements,” which in most cases in veterinary medicine are almost never supported by good evidence and have significant problems with quality control and potential risks. The fact that this use of supplements was guided by “muscle testing,” a term often used to describe the quack practice of applied kinesiology, is a further red flag. Inevitably, unproven but passionate claims about the value of raw diets appear as well:

I switched him off of kibble and on to raw venison mixed with simple fruits and vegetables. This had a huge impact on his skin.

However, the ultimate leap from dubious practices to quackery comes with the mention of Traditional Chinese Veterinary Medicine (TCVM).

…his skin was still red and inflamed, especially at night. Our doctor mentioned that in Chinese medicine, that was the Liver’s way of releasing toxins from the system so we then worked on purifying his liver and eliminating anything that might be an allergen…our integrative vet who took one look at Ceelo’s tongue and knew immediately that something was not right with his Spleen. He then did muscle testing to confirm his initial diagnosis. He prescribed a Chinese herb along with whole food and glandular supplements.

The principles of TCVM, including tongue diagnosis, are pre-scientific myths and metaphors that have never been reliably linked to health and disease through scientific research. While some of the herbal remedies used likely have beneficial compounds, the lack of a rational system for employing them and the lack of appropriate testing to determine their real risks and benefits make the system as a whole as likely to do nothing or even hurt patients as to benefit them. The addition of the nonsense of detoxification, applied kinesiology, and glandulars make this a classic description of pseudoscience which should serve as a warning to anyone thinking of bringing their pet to this veterinarian.

Unfortunately, the interpretation given by the client, and the message of the testimonial, is exactly the opposite. Despite the advocacy of multiple kinds of unproven and outright quack therapies, this vet has a happy, loyal client. Why?

Well, I don’t know anything about this doctor personally, but I suspect like most vets he or she is a genuinely smart, caring person. He/she probably demonstrates true concern for patients and clients alike and likely offers advice and recommendations in a confident, comforting manner. All of these characteristics are necessary to an effective veterinarian/client relationship. Unfortunately,  none of them have anything to do with whether or not the medicine being employed is effective or nonsense.

I also have clients who like me and trust me to care for their pets. Yet my approach to medicine is very, very different form that described here. The fact that we both have clients who are happy with the care we provide for their pets doesn’t say much about which style of medicine is superior because clients don’t judge us on the basis of the objective truth of our knowledge or effectiveness of our interventions, since these are not accessible to them.

“But,” this client might object, “the pet got better so that must be evidence the medical care was effective, right?” The core concept of the entire scientific method, and certainly of this blog, is that such anecdotes cannot be trusted and often do not mean what we think they mean. I have written about this often, but the bottom line is that it is deeply misleading to say that when an individual patient does well or badly that this validates or invalidates the treatment given. If this were true, science would be unnecessary, and yet the evidence of history is quite clear that science works far better than anecdotal methods or evaluating medical treatments. Here are a few reminders of why:

Medical Miracles: Should We Believe?
Testimonials Lie
Alternative medicine and placebo effects in pets
Placebo effects in epileptic dogs

Apart from the effect of a nice manner, and the ultimate positive outcome for the patient, the other reason why I suspect this client views her story as confirmation that she has a great vet is that she and the doctor share some key aspects of their world views. If this client were a scientist or a skeptic with a strong commitment to objective evidence and science-based medicine, I doubt she would have stuck with unproven recommendations based on pseudoscience for very long. We are naturally inclined to seek confirmation of our beliefs and to reject challenges to them, and this influences who we seek information from and how we interpret that information. Clients may like or dislike their vets personally, and they may believe the care their vets provide to be excellent or terrible based on the outcome, but they also tend to view more sympathetically advice consistent with their existing beliefs.

Bottom Line
It is natural to trust people we like, and this plays a large role in how pet owners judge their veterinarians. It is also natural to believe that something has been done right when things go well and that something has been done wrong when things go badly, though this is often not a reliable way to judge the quality of the care one’s pets receive. And finally, we are all predisposed to seek confirmation of our beliefs and to avoid challenges to them, which leads us to prefer vets who seem to think the way we do about health and disease, science and nature, and all the values-laden subjects that touch on veterinary medicine.

All of these inclinations are unavoidable, and for better or worse they influence the veterinarian-client relationship. Vets should recognize this and make their best effort to understand and respect their clients’ values and perspectives. We need not agree on everything with our clients, but we cannot help them or their pets if we cannot communicate effectively. I have plenty of clients with whom I disagree about the merits of specific therapies but with whom I get along great and who trust that I have their pets’ best interests at heart and the knowledge and skills to give them the best care.

On the other hand, clients should be aware of their own tendencies to judge their vets on the basis of factors that may not really have much to do with the quality of the medical care they provide. Without a thorough education in science and medicine, clients are stuck trusting their vets to some extent. Just as I cannot expect to effectively judge the competence or skill of my airplane pilot or tax accountant without having expertise in those domains, so pet owners have to recognize that while they have the right to control the care of their pets, they often don’t have the knowledge or skills to do so alone. If they did, they wouldn’t need a vet at all! And this means they must take a certain leap of faith when choosing a vet.

The key, then, is how one evaluates whether this faith is justified. The ability to empathise and communicate is essential, but it is not sufficient to mark a veterinarian as a skilled doctor. Ideally, an open and explicit adherence to established and accepted scientific standards of care would be the best way to know if your vet is doing the best they can for your pet. By this standard, an anecdote like the one on the AHVMF web site is a warning, not an endorsement!

Of course, if you doubt the value or reliability of science and science-based medicine, and if you already have a preference for the alternative philosophical perspective underling alternative medicine, well adherence to scientific principles and methods won’t seem a very reliable guide to quality to you. But at the least pet owners should be aware of the limitations of these natural human tendencies to trust those we like personally and who seem to agree with us. And we should recognize that individual anecdotes, good or bad, aren’t really a reliable way of evaluating the competence of those experts we hire to guide us in areas where our own expertise is insufficient, whether in medicine or other fields. Testimonials are far more persuasive than they are trustworthy.


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Is Cancer Caused by Bad Luck?

Why Ask Why?
There are many reasons people are interested in the causes of cancer in pets. On a purely emotional level, it is natural to ask “Why?” when something terrible happens, such as the diagnosis of cancer in a beloved animal companion. I suspect this is deeply rooted in human nature, in the drive to understand and predict the environment so that we can control it. On a rational level, of course, understanding the causes of cancer could be expected to give us exactly the control we yearn for, the ability to prevent it. Both our rational and emotional aspects push us to seek for causal patterns.

Unfortunately, there is a negative side to this search for causes. As Tim Minchin once remarked in another context, our drive to find the causes for things helps us to find meaning where there is none. We are sometimes so desperate to find a cause we can control, we allow our desperation to overwhelm reason and evidence and find causality where there is none.

This explains much of the dubious reasoning of alternative medicine. The ubiquitous and mistaken identification of mysterious “toxins” as the cause of so many ills, including cancer, is a product of our need to believe we can protect ourselves and our pets from these ills by avoiding or removing these toxins.

The entire pseudo-discipline of homotoxicology is predicated on toxins as the cause for all disease. And many other alternative approaches see toxins as a major threat. Detoxification is part of the claims made by proponents of so-called Traditional Chinese Veterinary Medicine (TCVM), veterinary homeopathy, herbal remedies for pets, energy therapies such as Reiki, and others. And toxins are routinely claimed as a cause of cancer in pets. Some of the toxins claimed to cause cancer include vaccines, commercial pet food, flea and tick control products, fluoridated water, electromagnetic radiation, and more.

Clearly, a major reason for citing such environmental factors as causes of cancer in our pets is to support further claims that we could prevent cancer by avoiding these factors or counteracting their ill effects. As I’ve already mentioned, this kind of reasoning is both a rational collection of hypotheses that can be tested and a deeply ingrained emotional need to seek control and protect ourselves, and our pets, from awful things like cancer. Unfortunately, the emotional aspect of this tendency often overwhelms the rational aspects, leading us to see cancer-causing poisons even where the evidence suggests they aren’t really present.

Certainly, some environmental factors, including things that can reasonably be called “toxins,” do increase cancer risk. The archetypical example is cigarette smoking, which is a clear and strong risk factor for certain kinds of lung cancer. Many other such risk factors have been identified and demonstrated to have causal relationships to specific cancers, from chemicals in food and water to infectious disease organisms and even medical interventions such as vaccination and chemotherapy. This is extremely useful because it allows us to avoid such exposures and potentially reduce the risk of cancer. It is almost a certainty that additional environmental risk factors for cancer will be found that are now unknown and that will increase our ability to reduce the occurrence of some cancers.

But how much of the cancer that occurs can we really blame on environmental factors? A new study has provided a suggestion that it may be less than we usually think.

The Study
Tomasetti, C. Vogelstein, B. Variation in cancer risk among tissues can be explained by the number of stem cell divisions. Science 2 January 2015: 78-81.

Some tissue types give rise to human cancers millions of times more often than other tissue types. Although this has been recognized for more than a century, it has never been explained. Here, we show that the lifetime risk of cancers of many different types is strongly correlated (0.81) with the total number of divisions of the normal self-renewing cells maintaining that tissue’s homeostasis. These results suggest that only a third of the variation in cancer risk among tissues is attributable to environmental factors or inherited predispositions. The majority is due to “bad luck,” that is, random mutations arising during DNA replication in normal, noncancerous stem cells. This is important not only for understanding the disease but also for designing strategies to limit the mortality it causes.

The basic events leading to cancer are pretty well understood. Cells in our bodies divide and reproduce all the time. If they didn’t, we could never grow, or repair wounds, or maintain the health and functioning of our organs. Mutations in some genes lead to uncontrolled division of cells, which can become a cancer. These mutations may occur in genes that stimulate cell division, genes that would normally control cell division, or other genes involved in the regulatory processes that prevent cancer but allow necessary growth and repair of tissues. The specific type of cancer depends on the type of cell and tissue involved and the particular mutations leading to loss of control over cell replication. The details are complex and not entirely understood, and they vary from cancer to cancer, but the general outline of the process is well-established.

The reason environmental factors can increase the risk of cancer is that they influence the occurrence of mutations. However, it is rarely as simple as one toxic exposure leading to one mutation leading to cancer. For cancer to develop, typically many things need to go wrong together, many genes to function abnormally at the same time. And environmental exposures are not on/off switches for genetic mutations. They influence the probability of such events in an often unpredictable way that is itself affected by dose, individual susceptibility, and many other factors.

One person may smoke for decades and never get lung cancer, while another may only smoke for a few years, or not at all, and get lung cancer anyway. And cancer is typically more common in some tissues that in others, sometimes in ways inconsistent with differences in potentially toxic environmental exposures. For example, the small intestine is constantly exposed to potential carcinogens from the environment, while such things very rarely ever reach the brain, yet brain tumors are far more common than small intestinal cancers. What the authors of this paper have done is offer a possible explanation for differences in the risk of different kinds of cancer: bad luck!

Basically, what they are arguing is that most mutations leading to cancer happen by chance, not as a result of an environmental or genetic cause. The way they evaluated this idea is by looking at the rate of cell divisions in different tissues. As I said before, cell division happens all the time as part of the normal functioning of our bodies. However, some tissues repair and replace cells more rapidly and more often than others, and this is reflected in a greater number of cell divisions occurring in the stem cells of those tissues, that is in the progenitor cells that are responsible for producing all of the new functional cells in each tissue. Because each cell division event is an opportunity for a mistake in the copying of DNA, a mutation, the more cell divisions that happen, the more opportunities for mistakes that can lead to cancer.

This study found a strong and consistent correlation between the rate of cell division in each tissue and the reported incidence of cancers from that tissue in the population. Here’s what that looks like graphically:

As you can see, cancers are more common in tissues with higher rates of stem cell division, consistent with the hypothesis that many cancers occur by chance, simply as a function of errors during normal cell division, not as a consequence of some environmental of genetic factor.

Of course, life is almost always more complicated than the simple hypotheses we come up with to explain it. The authors did some further analysis to try and separate the contribution of chance and other factors, such as environmental exposures and genetic predisposition, in the formation of particular types of cancer. What they found was that cancers can be separated into different categories, some more likely to be caused by environmental or genetic factors and some more frequently due to chance.

Cancers on the right and in blue are those for which genetic and environmental factors play a large part in the risk of their occurrence. Examples are lung cancer in smokers and head and neck cancers caused by the human papilloma virus (HPV). For the other cancers, in green on the left of the chart, chance mutations play a dominant causal role. Of course, chance plays a role in all types of cancer, since even people with known risk factors, like smoking or HPV infection, do not always develop cancer. Overall, the authors’ work suggests that about 65% of the difference in cancer risk between different tissues is due to differences in the inherent rate of cell division in those tissues, in other words to chance.

So What?
This paper has been interpreted in the media as indicating that most cancers are caused by bad luck (random mutation). As has been pointed out elsewhere, this isn’t really an appropriate interpretation of the statistics in this paper, which only tell us something about the difference in the rate of cancer development in different tissues, not the actual chances of cancer occurring in individuals. And as the authors themselves point out, the role of chance mutations compared to environmental factors is different for different cancers. It is likely, for example, that chance plays a pretty small role in the chances of a smoker getting lung cancer since the effect of smoking is strong. The devil is, as always, in the details, and the details are complicated.

What the paper does illustrate, however, is that chance does play a large role in the development of cancer, and in some cases in is likely the most important factor. Our natural inclination to seek preventable causes for disease, which is at least as much a psychological mechanism for controlling our fear as it is a rational approach to preventative healthcare, makes us resistant to the idea that much of the risk for cancer in ourselves, and potentially our pets, is due to chance, to luck. It may be disheartening to accept this since it implies we cannot control all the risks or prevent cancer from happening.

But knowing how nature really works is always better than relying on our fantasies of how we would like it to work. If we appreciate the role of chance in the development of cancer, this can provide many benefits. For one thing, we can use the knowledge to help us stop worrying unnecessarily over things we cannot control. And we can stop wasting time and energy trying to avoid environmental factors that probably have little, if anything, to do with the chances of developing cancer. Even more importantly, perhaps we can stop avoiding things that are actually more beneficial than harmful, such as vaccinations, if we understand the statistical reality that their contribution to cancer risk is often very, very small, and negligible compared with their beneficial effects.

Much of what happens to us in life comes down to chance, to luck. Certainly, we should make reasonable efforts to identify preventable causes for diseases like cancer. But we will be far more effective at maintaining and restoring health if we focus our attention and energy on things that actually matter, rather than obsessing about illusory risk factors that provide us only with comforting magic rituals rather than real preventative healthcare strategies.

If this study is borne out and it is true that most cancer arises from chance mutations rather than genetic or environmental risk factors, then we will help far more people and pets by focusing on early detection and effective treatment than by warding off imagined evil toxins through bogus practices like homotoxicology or other “detoxification” schemes.

Another potential benefit of recognizing the large role of chance in the development of cancer might be that we can stop blaming ourselves when our pets develop these diseases. So many of the testimonials I see for unproven, unscientific or outright quack therapies begin with heart-wrenching stories about the death of a beloved pet from cancer. The dark side of our obsession with finding and controlling risks is that we tend to feel we are at fault when something bad happens. This self-recrimination is not only unnecessary pain we cause ourselves, it is itself a potential source of danger to our pets when it drives us to seek protection from unproven and pseudoscientific approaches.

Recognizing the role of chance in the occurrence of cancer is not a cause for despair but an opportunity to reap the benefits of acceptance. Realizing that not everything can be controlled, we can avoid the pain and wasted energy of trying to control everything, the guilt when bad things happen anyway, and the dangers of choosing magic rituals to ward of imaginary causes of illness over sound, scientific approaches to preventing, detecting, and treating disease, including cancer.

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The Dangerous Allure of Alternative Therapies for Pets with Cancer

Most pet owners understand that science-based medicine is the best hope for maintaining and restoring health in their animal companions. The tremendous successes of preventative and therapeutic healthcare in the last couple of centuries is difficult to deny (though proponents of alternative medicine certainly try).

While there are plenty of obvious and dramatic successes for specific interventions, like vaccination and antibiotics, the real power of science-based medicine is in the use of systematic methods for learning about how nature works, and how disease comes about. A true understanding of how our bodies work and what goes wrong in illness is more likely to lead to effective disease prevention and treatment than an elaborate set of myths and metaphors with little connection to the reality of nature.

Unfortunately, it is all too easy to find such myth-based systems, applying treatments in complex and ritualized ways without doing the hard and important work of scientific investigations to evaluate the truth behind their systems or the real effects of their interventions. I’ve addressed the bizarre pseudoscientific theories of homeopathy and the pre-scientific mythos of so-called Traditional Chinese Veterinary Medicine here before.

Such approaches may seem at best quaint and anachronistic, at worst deluded, but for the most part even people who understand the value and importance of science and science-based medicine tend to view them as harmless. However, false beliefs about nature that are used to construct systems of medical treatment and aggressively marketed can be harmful, both directly and indirectly. Even a system like homeopathy, which ultimately sells only magic water as medicine, can cause harm when it is applied to serious illness and used to discourage or even supplant appropriate medical care.

A recent issue of the Integrative Veterinary Care Journal (IVC) devoted to alternative therapies for cancer illustrates the danger of such misguided approaches. Two articles, in particular, discussing naturopathic and homeopathic cancer treatment, reveal some of the core beliefs of these practitioners who, despite their talk of “complementing” conventional medicine, really have a view of health and disease incompatible with and deeply opposed to that of science:

  1. Health and disease are as much spiritual issues as they are questions about physical health.
  2. Conventional medicine is fundamentally mistaken in its understanding and less effective in its treatments than alternative therapies, and it is always harmful even when it seems to be helping.
  3. Alternative therapies can effect cures where conventional treatment cannot, and no scientific research is needed to prove this claim

It is easy to see how such beliefs and claims could be attractive to someone facing the frightening diagnosis of cancer in their beloved animal companion. It is also, hopefully, equally obvious that when such claims are untrue, they can do harm by leading vulnerable and desperate pet owners to make poor choices in the care of their pets. Despite the appeal of the marketing language used to promote such practices, if they are based on faulty understanding and their effectiveness is unproven or non-existent, then choosing these approaches when our pets are ill is not likely to benefit, and at least as likely to harm, the pets we want so much to help.

The first article describes a “naturopathic” approach to cancer treatment.

Fougere, B. Naturopathic oncology. IVC. Winter 2104/2015. 20-23.

Naturopathy is a rather vaguely defined approach to health that incorporates virtually every alternative therapy, from acupuncture to herbs and dietary supplements, from chiropractic to homeopathy and “energy medicine.” It even includes many perfectly conventional practices such as nutrition and exercise, which it disingenuously claims to be “alternative” therapies. Naturopathy is characterized mostly by a reverence for the concept of “natural,” despite the misleading and largely illusory nature of this term. Naturopaths decide, somewhat arbitrarily, which therapies are “natural” and which aren’t and then claim to prevent and treat disease by using natural therapies to support the body’s own defenses and healing abilities. A lovely concept if there were much evidence to suggest it was true, but for the most part there is not.

In this article, Dr. Fougere makes it clear that she believes naturopathy to be safer and more effective than conventional medicine, and she clearly illustrates her belief that the scientific understanding of disease is mistaken and irrelevant to naturopathic treatment.

The greatest joy of being involved in naturopathic oncology is that our toolbox is so much larger than the one other veterinarians draw upon. It is empowering to know that there is always something more than can be done to help our patients, and even more phenomenal to be able to improve their health well beyond expectations, and create “spontaneous remissions”—something that the veterinary paradigm says is impossible…

The notion that there is never a situation in which further treatment is not in the best interests of a patient is a significant cause of great suffering, in human and veterinary medicine. While we all want to have hope, and while unexpected positive outcomes can sometimes occur, it is naïve to believe that there are never situations in which continued treatment does more harm than good. Of course, Dr. Fougere would respond that this only applies to conventional treatment, since alternative therapies can magically have only benefits and no risks.

We emphasize therapies that are non-invasive and natural and that do not make our patients less well.

Such a claim has never been proven true when examined in the objective light of science. It flies in the face of the clear evidence that one does not get something for nothing in nature. When working with a system as complex and interconnected as a living organism, it is impossible to alter one aspect as we wish without unintentionally affecting other aspects, sometimes with undesired results. The only therapies with no side-effects are therapies with no effects.

But such facts don’t disturb Dr. Fougere, who makes it clear she has little use for the understanding of health and disease produced by science, regardless of how successfully it has improved all our lives.

The diagnosis of cancer is important, but the definitive diagnosis is not central to our approach…We need to address all aspects of health and well-being, including physical factors…environmental factors, spiritual aspects, and even genetic factors.

She claims her treatments go beyond the physical health of her patients and affect their spiritual health as well. Such claims are easy to make as they cannot be proven or disproven, only accepted or rejected on faith. This also makes them of little value, since accepting any one such claim means we must rationally accept them all, stripping us of any ability to tell true from false.

Such approaches to understanding the world are natural to human beings, and they have been employed since before written history. They also did almost nothing to improve our health and longevity in thousands of years, whereas a science-based approach has had clear and unprecedented benefits. There is a cost to such beliefs, as appealing as they may be, because they lead us to acting on claims that can never be meaningfully evaluated as true or false.

Dr. Fougere’s rejection of the scientific view of cancer goes beyond simply rejecting the value of specific diagnoses. She substitutes a common, and false, alternative theory of disease.

From a naturopathic perspective, cancer arises from an imbalance or accumulation of toxicity…

Such a view of disease as caused by vague “toxins” is a reincarnation of the evil humours and it exaggerates, distorts, and ignores real scientific understanding of environmental risk factors for disease. Such toxins are claimed to be everywhere, from our food, air, and water to the very medical therapies supposed to protect and heal us, such as vaccines and medicines. The lack of specificity and evidence makes such claims about disease being caused by toxins no different than claims about disease being caused by evil spirits and demonic possession. Once again, actually finding the toxins, proving they cause disease, and testing if and how one’s treatments restore health are all irrelevant. This is faith-based medicine at its finest.

Most of the specific therapies Dr. Fougere recommends have little to no evidence to show they benefit cancer patients. They often have mutually incompatible theories behind their supposed effects, which are conveniently ignores, and they are often illustrations of the anti-scientific world view underlying the whole practice of naturopathy. A few examples:

We use [acupuncture] routinely to enhance energy and well-being. [whatever these might be and however acupuncture might enhance them, all without any risk, of course]

Ideally, herbs are prescribed according to the patient’s vitality, energetics, symptoms, concurrent treatments, prognosis, and diagnosis. [the order in which these factors are listed is interesting, with anything objective or scientifically established last and anything subjective and immeasurable given greater importance.]

Detoxification is an herbal medicine principle in cancer treatment, because cancer is thought to be the end result of accumulated toxins in the body.

Herbs with antioxidant effects can reduce the side effects of chemotherapy and radiation….[There is, naturally, no mention of the fact that antioxidants can also reduce the effectiveness of chemotherapy (e.g. 1, 2) and even increase cancer risk. The myth that such things can only be beneficial and must be safe because they are “natural” is a dangerous one.]

Another article in the same issue makes similar, and even more absurd, claims:

Stieg, S. Homeopathy for cancer: A gentle approach to a cure. IVC. Winter 2104/2015. 52-55.

Given the overwhelming evidence that homeopathy is only a placebo, the very suggestion that it could be used to treat, even cure, cancer is so at odds with reality it is difficult to see how it is not malpractice. There is really no way such a therapy can benefit the patient, even though the therapeutic ritual might comfort an owner. And belief in such a patently false view of health and disease, which leads one away from the proper use of science-based diagnostic and therapeutic methods, is only going to lead to harm. Yet Dr. Stieg blithely suggests this nonsense is safer and more effective than conventional medicine.

Homeopathy…offers a gentle approach to cancer, treating not just the lesion or condition but the patient as a whole. General well-being is first restored while the cancerous condition is being abated or resolved, and is followed by a return of good health….It is a good alternative to an allopathic approach.

Armed with this delusion that homeopathy is actually an effective alternative to real cancer treatment, Dr. Stieg gives further examples of her complete dismissal of the entire basis of modern, scientific medicine.

While allopathic nomenclature may be helpful in understanding a clinical situation, general disease labels are not needed to find an accurate prescription in homeopathy since they do not describe what is unique to an individual patient.

In other words, homeopaths don’t care what your actual diagnosis or disease is. They choose their therapies, as we have seen, based on arbitrary factors on questionable relevance, like what kind of dreams you’ve been having, what time of day you feel worst, and so on. Knowing you have a particular cancer does not, apparently, help them decide how to treat you, but these sorts of extraneous personal details do.

The hubris displayed, in claiming clear superiority in goals, safety, and effectiveness over real medicine despite the extensive evidence to the contrary only adds to the clear message here: anyone trusting their animal companion to this sort of treatment is being dangerously misled.

Homeopathic treatment aims to cure the patient and have the cancer completely resolve, without causing harmful side effects or requiring repeated medication…The case studies accompanying this article demonstrate how the homeopathic treatment of cancer successfully returned the patients to health and provided an increased quality of life without surgery, chemotherapy, or harmful side effects.

Apart from the generally unreliable nature of anecdotes, one imagines it should be fairly easy to find examples of patients with cancers that resolved complete under homeopathic treatment since homeopaths don’t find “allopathic” diagnosis relevant or necessary and so may well not bothering confirming it before proceeding with treatment. I once had a client whose young, asymptomatic dog was diagnosed annually with some dire illness, often cancer, which I could never identify. Each time, this illness which could only be seen by the homeopath was also magically cured, all without a single outward symptom of illness. Miraculous indeed!

It sometimes difficult not to find such articles amusing in their clear lack of connection to reality. Yet they are actually more tragic than funny, because unfortunately they fool people into believing the practices discussed have real value. The majority of the specific therapies are untested, and the general approach flies in the face of established science.

This is not to say there cannot be any benefit from any of the specific therapies. Some of the things naturopaths recommend, such as a healthy diet and exercise, are certainly beneficial. However, there is also nothing “alternative” about these practices, and they are regularly recommended by science-based clinicians as well. Other therapies, such as herbal remedies, may well have benefits, but these are almost always unproven. What is crucial is that those which do have benefits will also have risks, and these are as unknown as any potential benefits without proper scientific study. And many of the therapies recommended, such as homeopathy and “energy” therapies, are patently useless.

The key problem is that using therapies with unproven or no benefits and unknown risks guided by pseudoscientific notions of how health and disease work, especially in place of therapies based on a sound scientific understanding of disease and for which the benefits and risks are well-established, exposes patients to unnecessary harm. Such an approach had better be capable of performing miracles because only a miracle, a special suspension of the natural laws that govern the physical world, could make such an approach more likely to help than to harm the patient. Unfortunately, humans relied on such approaches for most of our history, with terrible results. Science has more than proven that while it is flawed and imperfect, as all human endeavors are, it is a far better choice for us and for our pets.





Posted in General | 5 Comments

Science or Magic? A Illustration of Homeopathic Provings

One of the ways that homeopathy manages to look like a science, rather than essentially the practice of magic, is through the use of detailed and systematic methods that resembles those of real science. One example of this is the “proving,” or what is sometimes called a “pathogenetic trial.”

This experiment resembles clinical trials used in science-based medicine in some superficial ways, and it is often misrepresented as a form of research study. However, the fundamental purpose of true scientific research, including clinical trials, is to control for the misleading effects of various sources of error, most notably biases and other errors arising from subjective human observations. Provings, however, are entirely subjective and so have no control for such errors.

The core principle of homeopathy, that “like cures like” rests on the notion that if a homeopathic remedy causes a specific pattern of symptoms in a healthy person, that pattern of symptoms can be reliably associated with that remedy and used as a guide to when to employ the remedy in treating disease. If a patient has a pattern of symptoms that match those listed in homeopathic references for a particular remedy, that remedy might be the best one for that patient, regardless of what scientific medicine might consider his or her actual diagnosis.

This sound deceptively reasonable, until we look into how it works in detail. I have covered the concept of like-cures-like before, as have many other authors (e.g. Science-Based Medicine, Skeptic’s Dictionary). Basically, homeopaths accept a version of the ancient and widespread, and completely false, theory of sympathetic magic. This is the belief that things which have some sort of superficial resemblance must have a fundamental connection such that one can be used to manipulate the other. The voodoo doll is a classic example. In this case, homeopaths claim that substances which cause certain symptoms in healthy people should be used to cure the causes of those symptoms in the ill. This is a notion that has stubbornly resisted all attempts to prove it is actually true.

In any case, even if this notion were true, there are some pretty seriously problems with how the symptom pattern for a given remedy are defined and identified through provings. Basically, presumably healthy people (no systematic effort to ensure they are healthy is generally made) take a remedy and keep a diary of every experience, physical or mental, they have for a period of time afterwards. After the trial, homeopaths look at these diaries and decide what patterns of symptoms are meaningful, and this becomes the defining characteristic pattern of that remedy.

The subjective nature and potential for bias in this approach has long been recognized. One of the most incisive criticisms of hoemoapthic provings was written by Oliver Wendell Holmes in his Homeopathy and Its Kindred Delusions in 1842, while Hahnemann was still alive. Nothing of consequence has changed in the intervening 173 years.

The effects of drugs upon healthy persons have been studied by Hahnemann and his associates. Their results were made known in his Materia Medica, a work in three large volumes in the French translation, published about eight years ago. The mode of experimentation appears to have been, to take the substance on trial, either in common or minute doses, and then to set down every little sensation, every little movement of mind or body, which occurred within many succeeding hours or days, as being produced solely by the substance employed. When I have enumerated some of the symptoms attributed to the power of the drugs taken, you will be able to judge how much value is to be ascribed to the assertions of such observers.

The following list was taken literally from the Materia Medica of Hahnemann, by my friend M. Vernois, for whose accuracy I am willing to be responsible. He has given seven pages of these symptoms, not selected, but taken at hazard from the French translation of the work. I shall be very brief in my citations.

“After stooping some time, sense of painful weight about the head upon resuming the erect posture.”

“An itching, tickling sensation at the outer edge of the palm of the left hand, which obliges the person to scratch.” The medicine was acetate of lime, and as the action of the globule taken is said to last twenty-eight days, you may judge how many such symptoms as the last might be supposed to happen.

Among the symptoms attributed to muriatic acid are these: a catarrh, sighing, pimples; “after having written a long time with the back a little bent over, violent pain in the back and shoulder-blades, as if from a strain,”—”dreams which are not remembered—disposition to mental dejection—wakefulness before and after midnight.”

I might extend this catalogue almost indefinitely. I have not cited these specimens with any view to exciting a sense of the ridiculous, which many others of those mentioned would not fail to do, but to show that the common accidents of sensation, the little bodily inconveniences to which all of us are subject, are seriously and systematically ascribed to whatever medicine may have been exhibited, even in the minute doses I have mentioned, whole days or weeks previously.

Provings are still conducted in this way, with no real effort to control for bias of any kind. And the kinds of symptoms attributed to the remedies tested are as arbitrary and irrational as even. I recently ran across a beautiful example in a proving conducted by a senior homeopathy student about five years ago.

Homeopathic proving of Procyon lotor (Raccoon fur). Sonya McLeod and Kathleen Taylor, 2009.

That’s right. These homeopaths decided to test the potential medicinal properties of raccoon fur. Well, since they used mostly a 30c preparation, this means they mixed the fur (from a dead raccoon found “in the wild”) with a solvent (water or alcohol) and successively diluted it until there was no chance of any molecules of raccoon fur remaining. So actually they were testing the effects of water that had once had some raccoon fur in it. But the issue of ultradilute substances is a different subject.

At this point, it is also important to mention that what homeopaths consider relevant symptoms is quite different from what science-based medicine considers relevant. Homeopathy is ultimately a practice for healing spiritual ills, of which bodily symptoms are only one manifestation. So mental, emotional, even spiritual “symptoms” are included in the characterization of remedies and the evaluation of patients. Homeopaths also view as salient features like the time of day symptoms are experienced or the side of the body in which they manifest.

While this may sound thorough and “holistic,” it is quite misleading. Since no human is capable of considering the influence of everything in the universe on a patient’s condition, all practitioners make decisions about what is or is not relevant. Science used systematic methods with controls for bias and error to do this. Homeopaths just pick what to pay attention to and what to ignore with no objective attempt to determine which factors really are relevant to maintaining or restoring health.

If I have a dog who is vomiting, what they have eaten is very likely to be relevant to why they are vomiting and what can be done to help them. This has been established by extensive research into how the gastrointestinal system works and how various substances affect its function. The fact that my patient may dream of rabbits, may have been born under a particular constellation, or may live in a house with hardwood floors rather than linoleum are probably less likely to be relevant or useful facts. Without a systematic and objective process of establishing whether these factors are actually connected to disease or the success of treatment, we end up arbitrarily considering anything and everything, which is not a rational or efficient way to practice.

In the raccoon fur proving, 8 individuals were chosen to take the remedy, at a variety of doses and dilutions. None of the methods used in true clinical trials to control for the influence of differences between individuals or groups of subjects were employed. No effort was made to establish the pre-existing physical or mental condition of the subjects or to control for differences between the individual subjects or between the subjects and the population who might one day be treated with this remedy.

The homeopaths did include one individual who received a “placebo” (how this is defined in homeopathic trials is always problematic, since the actual test remedies contain no active ingredients). However, the authors write, “we decided to include symptoms experienced by the prover who took placebo as well.”

This is clearly inconsistent with the approach of scientific research, which uses placebos to control for the influence of belief and expectation on the reports of subjects in a trial. The authors of this proving justify including the individual receiving the placebo with reference to an essay which makes it clear, yet again, that homeopathy is a variety of religion or magic, not science. According to this author, placebo controls are unnecessary since it is not the remedy itself that influences subjects but the idea, intention, or “immaterial essence” of the remedy.

A proving begins, in a literal sense, with the intention to prove a thing, with it being imagined, identified, obtained, and possibly potentised. Should the name of the thing be kept under wraps, double blinded, picked at random out of a hat, the proving date sprung upon the proving group, nonetheless the event field of the proving is the moment in time that intention arose.

…The concept of participation mystique comes to mind in order to afford a description of this phenomenon. In the case of the School, provings have become a recognised corner stone of homeopathic training. This plus familiarity, shared endeavour and healing ideals combine to engender group consciousness and participation mystique. That those who did not ‘take’ the thing, that those who did not even know that the proving would take place within the group, had been affected demonstrates the dynamic nature of the phenomenon.

It is only matter that is bound to space and time. The immaterial essence of the thing, actuated by the intention of the proving group constellates the action field. Forgive me labouring the point: the thing that we are dealing with is essence, spirit, call it what you will, and is not bound within the constraints of space and time. Those who key into it are part of it irrespective of distance or time; they know it telepathically.

The action field of a proving is not necessarily set up by taking orally or sniffing, nor is it necessarily either substance or potency. It may be derived from and by these means or not. Directed meditation and attentive listening is sufficient to initiate and sustain a proving. We have invoked group provings by one member ‘holding’ the concept/image of a thing…Rajan Sankaran experimented with music provings, while at the School we have experimented with ‘thought’ provings. In none of these was pharmacy involved. There was no use of potency, no ‘memory’ of water, no nuclear or crystalline patterning, because there was no substance.

One can see pretty clearly why the claim that provings are in any way at all equivalent to scientific clinical trials is nonsense. The similarity is more that between astrology and astrophysics, or between meteorology and divination.

The symptoms reported in the raccoon proving, which presumably will be used to decide when to employ this remedy in treating actual patients, reads, in some ways, like a horoscope. Vague or ambivalent descriptions are given which could apply to anyone at one time or another, or patterns of completely opposite symptoms are recorded and both interpreted as resulting from the remedy. For example:

…there are periods of effort alternating with inactivity…there were days where they were very active and restless, alternating with times when they had no energy to do much of anything.

Many of the provers also experienced menstrual symptoms…Two of the provers had their periods come as early as 9 days early. One supervisor had intermittent bleeding that came and went. For two provers it either caused or cured heavy period flow.

Many of the provers experienced more ideas and flow of thoughts after taking the remedy.

Sometimes this rush of thoughts increased at night, preventing sleep. Other provers found it very difficult to think and to concentrate, like their minds had become foggy, becoming absentminded and confused.

For some provers, their normal anxiety was ameliorated during the proving. One supervisor experienced a pronounced anxiety on waking at 5am.

The subjective symptoms, including emotions and dreams, show such obvious bias associated with pre-conceptions about the nature and cultural symbolic attributes of raccoons, it is difficult to imagine anyone could be unable to identify this obvious bias.

A few of the provers felt dirty or ugly…There was also a lot about survival.

People needing this remedy will fight for their survival…There was a lot in the dreams about victimization and subordination, abuse, being attacked, and then fighting back or protecting oneself or others.

Many provers…had an increased need to take care of and nurture their children. Many also had dreams of family members. This theme of nurturing and family also came out in the dreams of many of the provers. This is a them common to all mammal remedies, including raccoons who can stay with their young for up to a year.

We also found it interesting that two of the provers had itching and dryness of the nipples. This symptom fits in with the theme of nurturing.

Fear of snakes is also common to all mammal remedies. This symptom showed up in a few separate dreams of one of the provers.

Some provers became sensitive to colour and to bright light. One prover had the desire to wear black, as she found bright colours too stimulating. We can guess this symptom may be related to the raccoon’s increased sensitivity to light since their eyes are suited to night vision.

There were lots of dreams about committing crimes, stealing, criminals, and police. One of the provers had her proving journal stolen during the proving. The raccoon’s reputation as a sneaky bandit and thief comes through very strongly in this proving.

Lots of dreams about food and eating. Many of the provers had increased appetite, perhaps mimicking the raccoon’s voracious appetite in the fall, in preparation for sleeping away the winter.

[Raccoons are] also excellent climbers. In the proving, many of the provers had dreams of trees, and of climbing those trees.

The symptoms attributed to the remedy included things which could not be seen in any rational way as related to the preparation tested except through magic. These included:

Provers and their supervisors often had difficulty getting hold of each other during the proving. At the extraction meeting, the master prover’s internet stopped working,

A few days before the extraction meeting, the master prover’s parking lot was flooded. [categorized with symptoms related by “Flow & Lack of Flow: Water and Dryness”]

As is often the case, the ideas put forward by homeopaths can, at first, seem rational and even superficially similar to scientific practices. However, any investigation into the details of their claims and methods makes it clear that this is a relic of spiritualism and faith healing with no fundamental similarity, or even compatibility, with contemporary science. The methods rely entirely on subjective personal experience and make not even the most minimal effort to acknowledge or account for the biases this introduces.

Posted in Homeopathy | 4 Comments

A Visit to Hogwarts: The BAVH Introductory Course in Homeopathy

One of the things I like best about homeopathy is that when I want to illustrate how fanciful and ridiculous the theories and beliefs of homeopaths are, there is no need to exaggerate or embellish their claims in any way. All that is needed to demonstrate homeopathy is nonsense and that homeopaths are ultimately faith healers who have rejected the very foundations of conventional science-based medicine is to allow them to describe their beliefs and practices in their own words. A fairly simple comparison of what they claim to reality makes the point quite clearly.

I recently took a brief online introductory course in homeopathy offered by the British Academy of Veterinary Homeopathy (BAVH). This was a free offering intended to lure veterinarians into their full introductory training course, which will set you back £1,300 (about $2100). The course made many of the usual claims about both homeopathy and conventional medicine and illustrated the deep inconsistencies in what homeopaths say and what they really practice.

Throughout the course, the instructors repeatedly emphasize that they accept science and evidence-based medicine and do not reject established healthcare. They then repeatedly emphasize, exaggerate, or manufacture flaws in science and science-based medicine and claim that homeopathy is fundamentally different, and superior, in both theory and practice.

For example, the stated aim of the course is “To enable and encourage veterinary healthcare professionals to integrate the discipline into their clinical practice and to facilitate this within the framework of an evidence based approach.”  However, the instructors repeatedly claim that homeopathy can replace conventional therapies and that homeopathy is fundamentally different, safer and more effective than conventional medicine. Here are a few examples.

Homeopathy can work where conventional treatment has failed.

These natural remedies do not have traditional side effects.

Homeopathy can, in many cases, avoid the need of using antibiotics.

[Homeopathy provides] the opportunity to cure an animal whereas with a conventional approach all you can do at best is to hope to control it with continuous medication or in the absolute worst situations to carry out euthanasia.

[Homeopathy] is an actual philosophy of health and disease, a different understanding of what health and disease actually is… than in current medicine.

This material seems more appropriate for Hogwarts than for a veterinary continuing education course. Let’s have a look at the content in a bit more detail.

An Introduction to Potion Making

The central tenets of homeopathic theory, which originated with the father of homeopathy, Samuel Hahnemann in the 18th century, are reviewed in this course. Generally, no effort is made to provide evidence that these are true, they are simply assumed or implied to be true.

  1. Law of Similars

I have covered this subject before, as have many other authors (e.g. Science-Based Medicine, Skeptic’s Dictionary). Basically, the homeopaths accept a version of the ancient and widespread, and completely false, theory of sympathetic magic. This is the belief that things which have some sort of superficial resemblance must have a fundamental connection such that one can be used to manipulate the other. The voodoo doll is a classic example. In this case, homeopaths claim that substances which cause certain symptoms in healthy people should be used to cure the causes of those symptoms in the ill. This is a notion that has stubbornly resisted all attempts to prove it is actually true.

2. Dilution and Succussion

The instructors acknowledge that one of the biggest stumbling blocks to acceptance of their claims is the fact that many homeopathic remedies are diluted far beyond the point at which any of the original substance could possibly be present. The instructor for this course appears to be trying to have his cake and eat it too. He claims that dilution is not necessary for homeopathic remedies, but then admits that “most of the remedies we use involve dilution way beyond Avogadro’s number.” He admits that homeopathic remedies are usually ultradilute but suggests that Avogadro’s number is no longer relevant for some mysterious reason because we now have quantum physics, which has supplanted Newtonian physics. He offers, however, no evidence for exactly how quantum physics invalidates basic chemistry, merely mumbling about “nanoparticles” and “hydrogen bonds” in a way that is supposed to imply some deep meaning but simply illustrates that he really doesn’t know and is just waving away the problem on faith alone.

If quantum physics had replaced Newtonian physics, I would expect we would be using quantum principles to magically transport airplanes instantaneously anywhere we wanted, rather than shooting them laboriously through the sky using old-fashioned Newtonian physics. Yet we are not.

Finally, the instructor claims it is not the dilution which makes a homeopathic remedy but the succussion. Unfortunately this is just a fancy word for “shaking,” and why shaking should transform water into a specific medicine with properties derived from a substance no longer present is not explained (or, I would argue, explainable). In any case, he undercuts this attempt to dodge the problem of dilution when he says, “dilution does add to the effectiveness of a remedy.”

Another instructor, in the “evidence-based” section of the course, uses almost exactly the same strategy. She begins by suggesting conventional scientific understanding of chemistry as an interaction between molecules is outdated and not applicable to homeopathy. The scientific view, “requires active substance in this old-fashioned kind of lock-and-key type mechanism.” This instructor also claims homeopathy does not require using ultradilutions, but then acknowledges that “homeopaths mostly do use high dilutions.”

She goes on to claim it is widely accepted that ultramolecular solutions do have activity despite this not being possible under the conventional understanding, and then makes a lot of vague references to various scientific-sounding phenomena like “thermoluminescense,” “NMR studies,” “epitaxy,” “nanobubbles,” “stabilized water clustering,” etc.  Again, there is no attempt at explaining what, if anything, this has to do with the magic of pure water have all sorts of potent and varied therapeutic effects.

This is a classic hallmark of quackery, using a lot of vague, “sciency” language without any actual understanding of the concepts referred to or any real theoretical or data-based connection between them and the claims they are implied to be supporting. All of this is part of the typical pattern of homeopaths acting as if their theories are established, accepted science despite the reality that they are accepted by almost no one except other homeopaths.

3. Individualization of Treatment

Homeopaths like to claim that they tailor their therapies to each individual’s personal needs, while conventional medicine treats patients as so many identical units. I’ve written before about this supposed individualization, and why it is complete nonsense.

Basically, the claim to individualize treatment ignores the whole issue of relevance. Since no human doctor is capable of considering the effect of everything in the universe simultaneously throughout all time on the condition of the patient before them at the moment, all of us must decide which factors are relevant and which aren’t. In scientific medicine, we use the accumulated results of scientific research to understand the relationship between biological processes and all the things that can influence them to bring about disease or to preserve and restore health. It is impossible to perfectly account for all possible factors, but as scientific knowledge grows, we get better and better at understanding what matters and what doesn’t in the care of each patient.

A good example of this is the gradually improving understanding of the white blood cell cancer known generally as lymphoma. Rather than being a single cancer, it is a collection of related but different diseases, and the differences that matter vary from those that can be lumped into broad categories and are common to many patients, down to those that are unique to each individual. We are constantly improving our understanding of these differences, and how they influence treatment, and we are embarking on an era in which we will eventually be able to tailor cancer therapies very precisely to the needs of each individual, through detailed analysis of the genome of each person and each cancer. This is not yet a reality, but it is a plausible future we can reach by hard work and patience.

Homeopaths, on the other hand, choose which factors are relevant to the individual in a subjective, haphazard way that is essentially arbitrary. For example, one instructor in this course indicates that one way to decide whether the homeopathic remedy arsenica album is appropriate for a given patient is the time of day their symptoms seem to worsen. Specifically, “all the symptoms…whatever they may be, are much worse around or just after midnight.” Whether you have vomiting or coughing, a fever or back pain, and regardless of what scientific medicine would determine to be the cause of your disease, this remedy is for you if you think, or your doctor thinks, the symptoms are worse during this magical hour of the day. If you think your symptoms are worse at another time, you might well choose a different remedy. This criterion is based on the uncontrolled, personal anecdotal experience of some homeopath and then blindly followed by subsequent homeopaths without any rational or scientific attempt to find a sensible explanation for why this might be true.

Many other similar criteria, including the emotional experiences of patients, the color or smell of body fluids, the character of pain, and others are assumed to be relevant to the treatment based solely on subjective experiences without any rational or plausible, much less scientifically demonstrated, relationship between these factors and the cause of illness or the success or failure of treatment. This is witchcraft, not science or medicine!

Homeopaths also like to complain that clinical trials don’t provide good evidence for how to treat patients because they rely on the experiences of a group of people, and every individual is different. Yet how do they decide which symptoms indicate the need for which particular remedy? Why through a type of test they call a “proving.” This basically involves giving a remedy to a group of healthy people and having them write down everything they experience, physical, emotional, spiritual, and so on, while taking the remedy. Homeopaths then look through these subjective diaries and subjectively decide which patterns are meaningful, and they then assign specific symptoms to the remedy. In the future, other homeopaths then look at these symptoms to help decide which remedy to use. This is simply basing the choice of treatment for a given patient on the experiences of a group of other people, just as is done in clinical trials. The only difference is that in provings no attempt is made to objectively measure anything, and all the data are subjective and subject to innumerable sources of uncontrolled bias.


Evidence-based Magic

Of course, as I’ve discussed previously, the use of language like “scientifically proven” and “evidence-based” has great marketing value for alternative therapies. This is because people, regardless of their philosophical perspective, recognize that science has given us far more reliable knowledge about the world than any other approach, and it has brought about a tremendous and unprecedented improvement in human health and well-being. However, homeopaths use such language in a completely dishonest and disingenuous way.

As already pointed out, the instructors in this course claim to be committed to scientific evidence, yet they belabor, exaggerate, or manufacture all the flaws of scientific research and suggest that their subjective and anecdotal methods are superior. In an entire lecture of this course devoted to discussing “The Evidence Base for Homeopathy” the instructor never once suggests that any tenet of homeopathy or any basis for homeopathic practice might be proven wrong by scientific research. Science is not used by such individuals as a method to develop knowledge and test beliefs but as a marketing tool to promote their faith.

This is clear from the beginning, as the instructor describes how she began studying and using homeopathy at a time when there was no research evidence at all to support it in veterinary medicine. She chose to study it anyway, however, because she already knew it worked based on her personal experience.

The instructor then lists the number of research studies she claims exist to support veterinary homeopathy, without discussing them at all. The strategy is clearly to say that studies exist and allow the listener to suppose they show homeopathy is effective. Having reviewed the evidence base for homeopathy myself in great detail (1,2), I have learned that in fact the sheer number of studies is meaningless since the overwhelming bulk of the evidence is too biased and poorly conducted to mean anything, and the best quality evidence consistently shows homeopathy is nothing more than a placebo.

The instructor then indicates that she does not, in fact, believe scientific clinical trials are necessary or relevant to homeopathy anyway, despite having just suggested they proved homeopathy works. She lists numerous real and imagined weaknesses of clinical trials, without ever addressing their strengths or the tremendous positive impact they have had on healthcare. She then says that homeopathy is buttressed by exactly the subjective evaluation of individual cases that science has proven to be so deeply unreliable:

Case based reasoning is solving a new problem by remembering a previous similar situation and reusing the information and knowledge from that situation…200 years of homeopathic documented case reports and pathogenetic trials form the basis of every prescription choice…alongside cured case analysis…If we look at the case report, perhaps it may be the gold standard [rather than randomized clinical trials].

The approach here seems to be to say that homeopathy is validated by science, but that science isn’t all that reliable, and anyway homeopathy doesn’t need to be validated by science because we already know it works. Needless to say, this is not a logic that is in any way compatible with evidence-based medicine.

The instructor does discuss a recent systematic review of veterinary homeopathic clinical trials, which I have evaluated previously. The conclusion of the review’s authors was that additional research is needed to validate homeopathy. My conclusion is that if the best evidence committed advocates of homeopathy can come up with after 150 years consists of two clinical trials, one of which is weak and the other shows no effect, then there is no reason to think more research will be of any use.

In any case, I found it interesting that the instructor repeatedly mentioned the problem of bias when questioning the value of clinical trials on pharmaceuticals and other conventional therapies, but she neglected to mention the fact that both authors of this systematic reviews are “employed by a homeopathy charity to clarify and extend an evidence base in homeopathy.” Neither does she acknowledge that almost all of the research evidence cited in favor of homeopathy is funded and conducted by advocates for the practice, and most of it is published in journals devoted to homeopathy or other alternative therapies. The problem of investigator and publishing bias cuts in both directions, but homeopaths conveniently ignore this when discussing studies that agree with their own bias.


Integrating Magical & Muggle Medicine

The final lecture in this course was a general discussion of so-called “integrative medicine” and why veterinarians should mix science-based medicine and unproven or nonsensical alternatives like homeopathy.  I’ve discussed before the misleading nature of this term (3, 4). Mark Crislip has probably most effectively characterized the integration of scientific and alternative medicine:

If you integrate fantasy with reality, you do not instantiate reality. If you mix cow pie with apple pie, it does not make the cow pie taste better; it makes the apple pie worse.

This lecture repeats many of the unsupported claims about the superior safety and effectiveness of alternative therapies. It conveniently ignores the fact that several of the various therapies recommended and used together are based on completely incompatible models of health and disease. The instructor claims that using this hodgepodge of approaches will:

Allow “less reliance on suppressive conventional treatment” with “no suppression of signs or symptoms for a later and much more vicious reappearance later, which is something we see with suppressive conventional therapies”

Integrative medicine “can work where conventional treatment has failed” and lead to “fewer drug side-effects, better clinical outcomes, [and] quality of life for patients and owners.”

She even goes so far as to hint at the truth homeopaths so often struggle to conceal–that homeopathy is ultimately a form of faith healing.

Hahnemann viewed the health of the body as dependant on spiritual health, and he saw disease as fundamentally not a physical abnormality but an abnormality of spirit. Curing disease, then, was a spiritual matter:

During health a spiritual power (autocracy, vital force) animates the organism and keeps it in harmonious order. Without this animating, spirit-like power, the organism is dead.

In disease the vital force is primarily morbidly deranged and expresses its sufferings (the internal change) by abnormal sensations and functions of the organism.

The affection of the diseased vital force and the disease symptoms thereby produced constitute an inseparable whole—they are one and the same. It is only by the spiritual influences of morbific noxae that our spirit-like vital force can become ill; and in like manner, only by the spirit-like (dynamic) operation of medicines that it can be again restored to health.

The instructor of this course references this spiritual orientation when she contrasts scientific medicine with homeopathy, revealing her view that they are fundamentally incompatible. The use of the word “dynamic” is intended to hide the fact that the real force referred to here, which Hahnemann also used the word dynamic to reference, is spiritual and supernatural:

Conventional thinking is based in the material world, with most current treatments and research being centered around genes and the biochemical pathways that are altered in the expression of disease.

Homeopathic thinking is based in the dynamic world with treatments based on symptom expression of the whole individual with symptoms and material changes being a consequence of dynamic disturbance and not a cause of disease.

This lecture also most dramatically paints a picture of harmful and ineffective conventional medicine contrasted with gentle and miraculous alternative medicine. Next to a picture of a dog looking sad, she describes how in conventional medicine “a failure to understand and explain the disease process often leaves the client with a pocket full of drugs, a dog that looks no better,  and a feeling of deep dissatisfaction.” Clearly, science-based medicine is really Sad Dog Medicine.

In conventional medicine “a failure to understand and explain the disease process often leaves the client with a pocket full of drugs, a dog that looks no better,  and a feeling of deep dissatisfaction.”

In conventional medicine “a failure to understand and explain the disease process often leaves the client with a pocket full of drugs, a dog that looks no better, and a feeling of deep dissatisfaction.”

Along with a photo of the same dog looking happy, the instructor explains how integrative medicine can improve client compliance and lead to fewer drug side-effects, better clinical outcomes, better quality of life for patients and owners.” Clearly, integrative medicine is Happy Dog Medicine!


Integrative medicine can improve client compliance and lead to fewer drug side-effects, better clinical outcomes, better quality of life for patients and owners.”

Integrative medicine can improve client compliance and lead to fewer drug side-effects, better clinical outcomes, better quality of life for patients and owners.”


The Ethics of Fairy Dust

There is nothing especially surprising or original in this course. All of the usual clichés, fairy tales, and misinformation associated with homeopathy are present. What is disturbing is that this course is offered as continuing education for practicing veterinarians. Veterinarians are legally required to update and advance their knowledge base to maintain their license to practice. This is intended to protect the public from outdated ideas and ineffective care. However, the purpose of such a requirement is defeated entirely when veterinarians can maintain their license by learning outdated ideas and ineffective care.

What is more, such courses can mislead veterinarians into believing homeopathy has some legitimate scientific basis and is something other than an 18th century pseudoscientific form of faith healing that functions only as a placebo. And the placement of the BAVH and its course alongside mainstream, reputable veterinary medical organizations and their science-based continuing education materials implies an equivalence that is entirely false. It is unethical to practice homeopathy on veterinary patients and to make false claims about it to animal owners and other veterinarians. Some veterinary and governmental organizations have recognized this and taken a principled stand in defense of the public and our patients. If only more would join them.

The British Veterinary Association-

The BVA cannot endorse the use of homeopathic medicines, or indeed any medicine making therapeutic claims, which have no proven efficacy.

The Australian Veterinary Association-

That the Board agreed that the veterinary therapies of homeopathy and homotoxicology are considered ineffective therapies in accordance with the AVA promotion of ineffective therapies Board resolution.

The AVMA Council on Research-

There is no clinical evidence to support the use of homeopathic remedies for treatment or prevention of diseases in domestic animals.

The Australian National Health and Medical Research Council-

NHMRC concludes that the assessment of the evidence from research in humans does not show that homeopathy is effective for treating the range of health conditions considered.

The United Kingdom House of Commons Science and Technology Committee-

In our view, the systematic reviews and meta-analyses conclusively demonstrate that homeopathic products perform no better than placebos. We could find no support from independent experts for the idea that there is good evidence for the efficacy of homeopathy.




Posted in Homeopathy | 8 Comments

Vaccination Protects Children from Allergies Later in Life

One of the innumerable complaints made about vaccination is that it “stresses the immune system,” and that this can lead to immune-system diseases, including allergies. Dr. Crislip at Science-based Medicine has already dealt with the notion of immune system overload, pointing out that our immune system is exposed to as many antigens in about a month of daily life as it is in the entire recommended childhood vaccination regime. Yet vaccine opponents continue to blame all sorts of health problems on damage to the immune system from vaccinations, including allergic diseases. A recent study in children challenges that claim.

Herbarth, O. World Allergy Organization International Scientific Conference (WISC) and Congress of the Brazilian Association of Allergy and Immunology. Abstract 1014. Presented December 7, 2014.

The study looked at about 2,200 children. In every group studies, including those considered at increased risk for allergies due to having parents with allergic disease, vaccinated children had LOWER rates of allergies than unvaccinated children.

As always, a single study is never the last word on any subject. And a small study in human children doesn’t rule out the possibility of some link between vaccination and allergies in dogs and cats. But in addressing concerns about potential adverse effects of vaccination, it is important we be guided by evidence, not mere theory or fear. There is now at least some evidence that vaccination not only doesn’t increase allergy risk but that it may be protective against allergies. Those who believe otherwise should bear the burden of providing evidence for their claims.

Posted in Vaccines | 6 Comments

The Fence-Learn to Love Nuance, Complexity, and Ambivalence

From the only humanist, atheist, skeptic rock star out there, Tim Minchin!


Posted in Humor | 2 Comments

Antibody Titer Testing as a Guide for Vaccination in Dogs and Cats

I have been involved in a number of discussions lately regarding the concept of testing antibody titers in lieu of vaccinating, and I thought it might be useful to summarize some of the issues involved in this complex topic. I will briefly explain the basic biology of immunization and then talk about the issues surrounding the usefulness of vaccine antibody titers.

How Vaccination Works
The immune system has many mechanisms for identifying and destroying infectious organisms, such as bacteria and viruses, in order to prevent or control disease. The details are bewilderingly complicated, and entire courses, even entire careers in science, are focused on trying to understand how this process works. There are a number of web sites that offer simple overviews of how vaccination stimulates the immune system to protect against infectious organisms (e.g. National Institutes of Health, Centers for Disease Control, National Network for Immunization Information).

Briefly, when a virus or bacterium invades the body, specialized cells that are part of the immune system begin to attack it. Some of these fight off the organism directly, but others communicate with the rest of the immune system to stimulate a host of different responses throughout the body. Part of this global reaction is a memory response. After an initial infection and illness, the immune system learns to recognize the organism so if it sees it again in the future, it can mount a faster and more effective response. Sometimes, this memory provides complete and lifelong immunity. However, sometimes, this immunity is incomplete or only temporary. The difference depends on a lot of factors involving the type of infectious organism and the individual’s immune system.

Vaccines teach the immune system to recognize an infectious organism without producing the actual illness. Usually, vaccines use a killed or weakened version of the infectious organism so the immune system can learn to recognize it without an actual infection and illness. In the future, then, the immune system of a vaccinated individual will be able to generate a faster, stronger protective response to the real organism, therefore avoiding an infection. Again, the effectiveness of vaccination and the duration of this immunity to infection vary and depend on many factors.

There are two basic components to the immune system’s memory of a disease-causing organism. One, called humoral immunity, involves producing proteins called antibodies. These are proteins that recognize a particular organism and help the body to fight it. Antibodies are produced for almost every organism we encounter, naturally or through vaccination, so we all make antibodies to thousands of organisms all the time. We can also get some antibodies from our mothers as babies, through nursing.

The other aspect of the memory response is called cell-mediated immunity. This involves special cells in the immune system which learn to recognize and attack invading microorganisms.

So when we talk about measuring antibody titers, we mean that we are measuring the amount of antibodies in the bloodstream which are produced in response to infection or vaccination for a single microorganism. If we have had an infection or vaccine in the past, we will often have antibodies against that particular organism. These may last for weeks, months, or years. It is important to realize, however, that having antibodies does not always mean we are immune to an infectious organism. If we have too few antibodies, we may be susceptible. And in the case of some organisms, having antibodies is not enough to fully protect us, so we may be susceptible no matter how many we produce. And since we produce antibodies during an infection, having them may not mean we have been vaccinated or had past exposure to an infectious disease, they may simply mean we are currently infected with that disease!

The challenge, then, in using antibody levels to make decisions about vaccination is that the significance of the measurement depends on the details of the biology of the particular organism. When we talk about antibodies and vaccination, we have to talk about one specific disease at a time, because the rules that apply to one disease won’t necessarily apply to another.

Core Vaccines & Antibody Titers
As I mentioned above, for some diseases antibody titers don’t represent immunity or susceptibility very well. Antibodies to common cat disease, for example, such as Feline Herpes Virus (FHV) or Feline Leukemia Virus (FeLV), don’t correlate well with protection against infection. A cat with a high antibody titer against FHV may very well still be susceptible to infection and may benefit from vaccination. And a cat with a high titer for FeLV is probably already permanently infected rather than immune. Antibody titers for rabies and Feline Panleukopenia, however, do correlate with immunity against these diseases.

For dogs, the most important core vaccines are for Canine Distemper Virus (CDV), Canine Parvovirus (CPV), and Rabies. In the case of these diseases, a high antibody titer does usually mean the dog is immune, which would mean additional vaccination for those diseases is not needed at the time the titer is measured. However, the rate at which individuals lose immunity to specific diseases varies quite a bit, so there is no way to predict based on a single titer when that individual will become susceptible again or need additional vaccination.

What most people don’t realize is that while a high titer for some disease, such as CDV, CPV, and Rabies, means a dog is probably immune, a low titer does NOT mean the dog is susceptible and needs to be vaccinated. That is because the other component of the immune system’s memory response, cell-mediated immunity, can protect against infection sometimes even when measured titer levels are low.

So a positive or high titer may mean no vaccine is needed right now, but a low titer does not mean a dog should be vaccinated. In the case of a low titer, we have no way of knowing if that dog is susceptible to these diseases or not.

Specific Titer Tests
You may wonder how we know whether or not a certain level of antibodies measured in the blood mean that individual is protected against that disease. The answer is that the only way to know is through challenge testing. This means that we have to measure antibody levels in a number of individuals with a variety of different titers, then try to infect them with the specific disease we are studying and see which ones get sick and which don’t. This is how cutoff levels for antibody titers have been determined for CDV, CPV, Rabies, and other canine and feline vaccine-preventable disease.

This kind of challenge testing may only be accurate for a specific titer testing method. So if two different laboratories use two different types of titer test, the titer level that is protective will be different, and both would need to do challenge testing to figure out what titer level is protective for the specific test method they each use

Obviously, there are ethical issues associated with this kind of research, and so very little of it is done any more. Most titer tests available have not been validated by challenge testing but have simply been compared to tests which have. This may mean that the values used to determine if an individual is immune to a particular disease are accurate, but it is also possible that they are not. So there is usually some uncertainty about what a “protective” titer really means.

As an example, one popular in-house antibody test sold to veterinarians is called Vaccicheck. This test provides a simple measure of roughly how much antibody an individual dog has against CDV, CPV, and also Canine Infectious Hepatitis. Again, no challenge studies have been done to validate the specific cutoff this test uses, but the test has been compared to what are considered “gold-standard” titer tests. For the canine Vaccicheck test, here are the results of one such study:

B.A. Butler; P.C. Crawford . Accuracy of a Point-of-Care Immunoassay to Determine Protective Antibody Titers For Canine Parvovirus and Canine Distemper Virus. ACVIM Forum, 2013.

Immunoassay sensitivity was 97% for CDV and 99% for CPV. Specificity was 75% for CPV and 79% for CDV. Many of the false positive reactions were in samples with antibody titers near the reference laboratory PAT cutoff. Overall diagnostic accuracy was 90% for CDV and 94% for CPV.

Sensitivity, specificity, and both positive and negative predictive value are somewhat complex statistical topics. Basically, this study showed that when the Vaccicheck test indicated a negative result (low titer level), this was very accurate. Of course, this result doesn’t help us make vaccination decisions because it doesn’t tell us whether or not the individual is vulnerable to infection since cell-mediated immunity may still be providing protection.

The accuracy of a positive result (high titer level) was also pretty good, but not nearly as good as that of a negative level. This means that some dogs will have a positive test, suggesting they are protected, when they really don’t have a high level of antibodies and may or may not actually be immune.

So overall, this test will usually tell us when a dog has a high CDV or CPV titer and does not need to be vaccinated, though it will get some of these wrong. It will more reliably tell us when a dog has a low titer level, but that doesn’t help much us decide if that dog needs to be vaccinated or not. Generally, other in-house titer tests have similar pros and cons. You can see that it can be difficult to make vaccination decisions based on this kind of test.

Legal Issues
The legal requirements for vaccination vary by county and even municipality, so it is difficult to make accurate generalizations. Most jurisdictions only require proof of vaccination against rabies, since that is the disease of greatest concern with respect to human health. Most jurisdictions also do not allow titer testing in lieu of vaccination for rabies, though some may. And when titers are used, the only test that is usually accepted is the FAVM from the Kansas State University veterinary laboratory. So while titers are representative of immunity for rabies in dogs and cats, and thus can indicate when vaccination is not needed, they are not often useful practically because they don’t fulfil the legal vaccination requirements.

Titers may or may not be accepted by other parties that require vaccination for other diseases, such as boarding kennels, training facilities, and dog show organizers. Which tests, if any, are accepted is up to the individual organization. So titers may not always be useful in avoiding vaccination if we are vaccinating specifically to meet a legal or institutional requirement.

Vaccine Safety
I have written many times about the subject of vaccine safety. While I believe in avoiding unnecessary vaccination, and while my own recommendations to clients often lead to less frequent vaccination than commonly practiced or suggested in some guidelines, I believe that the fear of vaccines that leads many people to desire to reduce vaccination is unjustified. Vaccines are very, very safe, and many of the specific concerns, such as mercury in vaccines, and autoimmune disease from vaccination, are unproven, exaggerated, or just plain untrue. So while I believe the evidence indicates we can safely vaccinate most dogs and cats far less often than has traditionally been recommended, I do not believe we should use titers or other methods to reduce vaccination out of fear.

Children in the United States and Europe are experiencing a growing risk of preventable infectious disease, and the real harm that comes from such infections, specifically because of a decrease in compliance with sound, evidence-based vaccination recommendations. Mumps, measles, and whooping cough, for example, are injuring and killing children who could have been protected, due mostly to fears among parents which are based on misconceptions or lies. I believe we must be very careful not to follow this same path in veterinary medicine.

So while I see utility for antibody titer testing in some situations, it is distressing that some companies selling these tests seem to be marketing them using fear and the testimonials of individuals who are known opponents of science-based medicine and promoters of irrational anti-vaccine positions and unscientific alternative therapies. Dr. Shawn Messonier, Dr. Karen Becker, Catherine O’Driscoll, and Dogs Naturally Magazine, are some of the entirely unreliable sources to which the Vaccicheck company refers pet owners in promoting their product. We will do far more harm than good for our pets if we base our vaccination decisions on pseudoscience or irrational fear, which is what these individuals often promote, rather than sound science.

Additional Information

  1. Here is a very clear, informative article on the use of antibody titers in guiding vaccination practices:

Ford, RB. Antibody titers versus vaccination. Today’s Veterinary Practice. May/June, 2013.

2. Here is the American Animal Hospital Association (AAHA) Canine Vaccination Guidelines, which talks specifically and in detail about particular vaccines and comprehensively reviews the available evidence on efficacy, safety, and duration of immunity. The guidelines specifically address titers and generally recommend some uses of them:

Despite the confusion and controversy surrounding antibody testing, these serologic tests are useful for monitoring immunity to CDV, CPV-2, CAV-1, and RV…. The tests are also medically useful to ensure that a dog responds to a specific core virus vaccine and/or to determine if immunity is present in a previously vaccinated dog. Those tests are also used to demonstrate protective immunity as well as DOI.

3. The American Veterinary Medical Association (AVMA) Report on Cat and Dog Vaccines also addresses the subject of titers, but the conclusion is somewhat different from the AAHA guidelines:

…it is currently impossible to determine the immune status of an animal relative to all the infectious diseases of concern without conducting challenge testing. Further, serologic results do not appear to be a sensitive indicator of immune response for some diseases or vaccines in cats and dogs. It was concluded that there are variations within and among laboratories, as well as a lack of validated sensitivity, specificity, and confidence intervals, leading to the conclusion that serologic testing is generally unreliable….

…higher serologic titers are generally associated with greater resistance, but…it is possible for an animal with no titer for a specific organism to have solid resistance to challenge. Conversely, an animal with a titer that is generally regarded as protective for a specific organism may also become ill as the result of challenge, possibly because of overwhelming exposure or immune suppression…

…practitioners are cautioned to consider carefully whether the test proposed has been appropriately validated, thereby providing a predictive value for whether the animal needs to be revaccinated, and includes confidence intervals to help the practitioner determine the risks and benefits of relying on the test results. Practitioners should also determine whether a selected laboratory has a quality control program sufficient to make the test results reliable.

4. The American Association of Feline Practitioners (AAFP) has also issued guidelines for vaccination of cats. These guidelines only comment briefly on the use of antibody titers (also called serology):

It is important to be aware that a variety of methods…are utilized to determine titers.…Titer results in individual cats determined at the same point in time, therefore, may vary depending on the methodology used. When electing to submit serum for antibody titers, it needs to be appreciated that a ‘positive’ antibody titer result obtained on one day is not necessarily predictive of a ‘positive’ titer at any point in the future.

In general, cats having a ‘positive’ antibody titer against FPV are immune. In fact, the protective immunity that develops following FPV vaccination is expected to be sustained for several years. By contrast, serum antibody titers for FHV-1 and FCV may not necessarily correlate well with protective immunity and should not be used to predict protection in the future. Antibody titers to FeLV and FIV do not correlate with immunity and should not be used to determine the need for vaccination. Although feline rabies titers can be determined (by a certificated laboratory) in individual animals, a rabies titer is only an indication of serological response to vaccination. Rabies titers are not recognized as an index of immunity.

In addition, the absence of significant levels of antibody (a ‘negative’ titer) is not necessarily an indication of susceptibility… In some diseases (eg, FHV-1), cell-mediated immunity is important and a cat may be immune even though no antibodies are detectable.

Because antibody titers may not reliably correlate with, or predict, the degree of protection or susceptibility for an individual cat, the Advisory Panel recommends employing defined revaccination intervals rather than measuring antibody titers to assure protection.

Bottom Line
Vaccine titers can tell us an individual is immune and does not need to be vaccinated for some specific diseases. For other diseases, a positive titer does not reflect immunity. And a negative titer cannot reliably tell us if an individual is susceptible and need additional vaccination. Therefore, the usefulness of titers in determining if an individual needs to be vaccinated is quite limited. This usefulness is further dependent on the specific kind of titer test used and how it has been validated.

Titers can lead to a reduction in unnecessary vaccination in some cases, if an individual has a titer that can be identified as representative of immunity. However, titers can also lead to an increase in unnecessary vaccinations if animals with negative titers are routinely vaccinated even though they may already be immune.

Titers cannot generally be substituted for legal vaccination requirements, particularly for vaccination against rabies

The vaccines we use are extremely safe, so we have to remind ourselves and our clients that when in doubt it is probably far safer to vaccinate than not to vaccinate, unless there is some know history of adverse vaccine reaction, autoimmune disease, etc. The resurgence of vaccine-preventable disease in children following the decline in vaccination rates is well-demonstrated, and we don’t want to go down that road.

Using scientific evidence concerning the duration of protective immunity following vaccination in a population, and the existing guidelines based on this evidence, is probably a more appropriate strategy for determining how often to vaccinate individuals than is the routine use of antibody titers. Current guidelines for specific vaccines are based on a comprehensive review of existing evidence, and they can be updated as new evidence emerges. While titers may have use in some specific situations, they are not a simple, universal substitute for rational, science-based vaccination guidelines, and they do not offer as reliable an “individualization” of vaccination recommendations as some promoters suggest.

Posted in Vaccines | 7 Comments