Some infections can be eradicated from the face of the planet. Smallpox is the one example of disease eradication to date. Smallpox still exists in US and Russian labs, but there has been no wild cases since 1977. It is, like the Dorothy, history.
Why were we able to eradicate smallpox? Three reasons:
1) There is only one form of smallpox. Unlike influenza that changes from year to year. So only one vaccine needed.
2) By what appears to be a once in a universe miracle, every county cooperated with the WHO (much like we all cooperate with the IRS) so the entire planet received the vaccine. Once enough people were vaccinated, the disease was unable to perpetuate itself and spread and so died out.
3) Unlike bacteria, there are no asymptomatic smallpox carrier states. Eradicable viruses usually cause symptomatic disease and do not result in asymptomatic, infectious carrier states that serve as a reservoir for infecting others. HIV and Herpes cause chronic asymptomatic infections and will probably never be eradicated.
There are other diseases that are theoretically eradicable, like measles and polio. They have one antigenic type, have no carrier state and, if the entire world could be vaccinated, the disease would cease to exist in the wild. I am sure there would be biologic weapons labs that would always carry a vial or 2 of every infection. Just to be safe.
Much to my surprise and delight, my recent blog post about Jenny McCarthy’s “educational” video was picked up by several other blogs and websites, resulting in a small flood of emails applauding my efforts to expose dangerous pseudoscience. I had braced myself for what I assumed would be an onslaught of hate mail (what else would irrational folks do about a sensible warning message?) and found that instead I received a small number of high-fives from advocates and health organizations committed to cutting through the rhetoric and providing accurate information about vaccines. Perhaps the hate is still in the mail?
I began wondering who is in the majority on the issue of vaccines – those who want to study concerns carefully and accept what the science shows, or those who are fixated on blaming vaccines for diseases they don’t cause, despite all evidence to the contrary.
Since the latter are louder than the former, one does tend to feel as if the world has gone a bit nutty. And when celebrities like Oprah Winfrey promote the unfounded anti-vaccine rhetoric of Jenny McCarthy, sensible parents across the country begin to shudder. But when will this shuddering lead to action?
In the US children must have proof of vaccination before entering the public school system, although it is becoming easier in many states for parents to gain exemptions from this requirement. In the UK there is no such requirement. This distinction has allowed for a comparison of the impact of scaremongering about the safety of vaccines and the effectiveness of campaigns to improve vaccination rates.
In the UK the scare that the MMR vaccine may be connected to autism (it isn’t) triggered by the bogus study by Andrew Wakefield resulted in a precipitous drop in vaccination rates down to about 78% overall. This is far below what is necessary for herd immunity, when immunity is prevalent enough to prevent a disease from spreading around a population. And the 78% figure is an average – but there are pockets where the number is even lower. This resulted in a surge of measles – from a low of less than 100 cases per year to 1,348 cases in 2008. The surge contniues despite an aggressive campaign to inform the public about the safety of the MMR vaccine.
By contrast the US has seen continued high overall vaccination rates of about 90%. The MMR and other vaccine scare came to the US a bit later than the UK but it is in full swing here, without much effect on overall vaccination rates. However, we are beginning to see the emergence of low vaccination rates in specific communities, with subsequent outbreaks of measles (131 cases in 2008), mumps, and whooping cough.
Unfortunately, a frequent topic on SBM has been the anti-vaccine movement, personified these days by celebrity spokesmodel for Generation Rescue Jenny McCarthy and her dimmer than dim boyfriend comedian and actor Jim Carrey. Unfortunately, it is a topic that is unlikely to go away. We’ve all speculated why the anti-scientific emotion-based notion that vaccines somehow must cause autism persists in spite of mountains of evidence to the contrary, but I think the question goes much deeper than that because it’s not just about vaccines. The anti-vaccine movement is but one of the most visible components of a much deeper problem in our public discourse, a problem that values feelings and personal experience over evidence, compelling stories and anecdotes over science.
I’m referring to the Oprah-fication of medicine in America.
The Centers for Disease Control (CDC) currently recommends that children 6 month to 18 years old receive an annual flu vaccine. There are two types of flu vaccines used in the US: a live attenuated virus (LAIV) and a trivalent inactivated virus (TIV) vaccine. Both are safe and effective – while efficacy varies from year to year, they are 70-90% effective in healthy adults. Efficacy is young children appears to be slightly less, about 66%.
There remains, however, many sub-questions about the flu vaccines and by the time researchers have thoroughly explored them vaccine technology is likely to have progressed, and therefore any new vaccines will have to be tested all over again.
One of those sub-questions about vaccine safety and efficacy is the net effect of the flu vaccine in children with asthma. Some have raised concerns that the vaccine may exacerbate asthma, a 1-2% increased wheezing and 3% increased hospitalizations have been reported, although so far the bulk of the data suggests that both types of flu vaccines are safe in children with asthma. There is evidence to suggest that the LAIV may be superior to the TIV in children, particularly with asthma.
We’ve written a lot about anti-vaccine zealotry on this blog, as Steve and I take a particular interest in this particular form of dangerous pseudoscience for a number of reasons. One reason, of course, is that the activities of antivaccine groups like Generation Rescue and its spokesmodel since 2007 (Jenny McCarthy, a frequent topic on this blog) have started to frighten parents about vaccines enough that vaccination rates are falling well below that required for herd immunity in some parts of the country. Indeed, McCarthy, at the behest of her handlers in Generation Rescue, serves up a regular “toxic” brew of misinformation and nonsense about vaccines, most recently in a video that was the subject of a post by Val Jones about her unbelievably pseudoscience-laden blather. Truly, it has to be seen to be believed. Meanwhile, Generation Rescue has sent McCarthy on a media propaganda tour for her latest antivaccine pro-quackery book and set up a misinformation-laden propaganda site called Fourteen Studies (blogged about by Steve Novella, Mark Crislip, and, of course, yours truly) in which they attack well-designed studies that have failed to confirm their pet idea that somehow, some way, vaccines must be the cause of autism. And, when their pseudoscience is criticized, the antivaccine movement has a tendency to launch vicious ad hominem attacks, as they recently did against Steve Novella and have done multiple times in the past against me.
However, there is one other consequence of the antivaccine movement, however, and it is at least as important as the public health implications of the potential dimunition of herd immunity caused by the fear mongering of groups like Generation Rescue. That consequence is the cottage industry of “biomedical” treatments to which desperate parents subject their children. Gluten-free diets, chelation therapy (which has caused deaths), hyperbaric oxygen chambers (a recent story described a child getting severely burned when one of these caught fire), autistic children have been subjected to it all. But of all the biomedical woo to which autistic children have been subjected, one form of woo stands out as being particularly heinous. Indeed, I agree with our fearless leader Steve in characterizing it as an “atrocity.”
I’m referring to Mark and David Geier’s favored “treatment” for autistic children, namely a drug called Lupron.
I’ve been fairly quiet about Jenny McCarthy’s campaign against childhood vaccinations, partly because Dr. David Gorski has covered the issue so thoroughly already, and partly because of my “do not engage” policy relating to the deeply irrational (i.e. there’s no winning an argument with “crazy.”) But this week I was filled with a renewed sense of urgency regarding the anti-vaccinationist movement for two reasons: 1) I received a personal email from a woman who is being treated with hostility by her peers for her pro-science views on vaccines and 2) a friend forwarded me a video of Jenny McCarthy speaking directly to moms, instructing them to avoid vaccinating their kids or giving them milk or wheat because of their supposed marijuana-like addictive properties.
My inaugural post was about vaccines, and I promised that I wouldn’t write exclusively on this topic. But something rotten is brewing in the state of Georgia and this story is just too important to ignore.
The first successful challenge to the National Childhood Vaccine Injury Compensation Act (NCVICA) has taken place in Georgia, and we all should be just a little bit worried. In Ferrari v. American Home Products Corp., the plaintiffs, Marcello and Carolyn Ferrari of Atlanta, have sued American Home Products Corp. (otherwise known as Wyeth) and the co-defendant GlaxoSmithKline, claiming that the vaccine preservative thimerosal led to their son’s autism. The consequences of this ruling could effect the health of the entire nation. To understand why, we need to delve a bit into what the NCVICA is exactly, and why it was created in the first place.
I realize that our fearless leader Steve Novella has already written about this topic twice. He has, as usual, done a bang-up job of describing how Arianna Huffington’s political news blog has become a haven for quackery, even going so far as to entitle his followup post The Huffington Post’s War on Science. And he’s absolutely right. The Huffington Post has waged a war on science, at least a war on science-based medicine, ever since its inception, a mere two weeks after which it was first noticed that anti-vaccine lunacy ruled the roost there. Because I’ve had experience with this topic since 2005, I thought I’d try to put some perspective on the issue, in order to show you just how pervasive pseudoscience has been (and for how long) at the blog whose name is often abbreviated as “HuffPo.”
Arguably the most difficult aspect of science-based medicine is where the rubber hits the road, so to speak. That’s where scientists and physicians take the results of preclinical studies performed in vitro in biochemical assays and cell culture models and in vivo in animal models to humans. There are numerous reasons for this, not the least of which that preclinical models, contrary to what animal rights activists would like you to believe, do not predict human responses to new therapeutic agents as much as we would like. However, the single biggest reason that we cannot answer questions in human studies as easily as we can in cell culture and animal studies is ethics. Of course, answering questions using cell culture and animal studies is not “easy,” either, but performing studies using human beings as subjects is an order of magnitude (at least) more difficult because the potential to cause harm exists, and if harm is caused by the experimental treatment under study, that harm will be done to human beings, rather than cells in a dish or mice bred for research.
The “gold standard” type of study that we do to test the efficacy of a new drug is known as the randomized, placebo-controlled, double-blinded study, often abbreviated RCT. Indeed, this remains the gold standard and is accorded the highest level of “power” in the framework of evidence-based medicine. Of course, as we have argued time and time again, using the RCT to test therapies that are incredibly implausible on a strictly scientific basis (homeopathy or reiki, for instance) inevitably leads to numerous “false positives” in which the therapy appears to produce results statistically significantly better than the control. John Ioannidis has done numerous clever analyses that demonstrate how easily clinical research is led astray if it is not grounded in scientific plausibility. Indeed, the probability of false positive studies increases, the more improbable the modality. It is for these very reasons that we have proposed the concept of science-based medicine, which takes into account estimates of prior probability based on preclinical studies and basic scientific principles, rather than evidence-based medicine, which does not. Indeed, Wally Sampson has even proposed a “plausibility scale” for rating RCTs, and Steve Novella has pointed out how difficult it can be to interpret the medical literature.