While doctor visits for influenza-like illnesses seem to be trending downward again, and “swine flu” is becoming old news, I’d like to draw attention to an H1N1 story that has received very little coverage by the mainstream media.

Doctors in several states can now protect their most vulnerable patients from the H1N1 virus without worrying about breaking the law. In order to save lives, several states have announced emergency waivers of their own inane public health laws, which ban the use of thimerosal-containing vaccines for pregnant women and young children.

Legislators in California, New York, Illinois, Missouri, Iowa, Delaware, and Washington state have enacted these science-ignoring laws in response to pressures from the anti-vaccine lobby and fear-struck constituents. Except for minor differences, each state’s law is essentially the same, so I will focus on the one from my state of New York.

New York State Public Health Law §2112 became effective on July 1, 2008. It prohibits the administration of vaccines containing more than trace amounts of thimerosal to woman who know they are pregnant, and to children under the age of 3. The term “trace amounts” is defined by this law as 0.625 micrograms of mercury per 0.25 mL dose of influenza vaccine for children under 3, or 0.5 micrograms per 0.5 mL dose of all other vaccines for children under 3 and pregnant women. Because thimerosal (and thus, mercury) exists only in multi-dose vials of the influenza vaccines (both seasonal and novel H1N1), this law really only applies to these vaccines. The mercury concentration of the influenza vaccines is 25 micrograms per 0.5 mL, which therefore makes their use illegal. Unfortunately, the only form of the H1N1 vaccine initially distributed, and that could be used for young children and pregnant women, was the thimerosal-containing form. The thimerosal-free vaccine was the last to ship, and in low supply, and the nasal spray is a live-virus vaccine, not approved for use in pregnancy or children under 2. That meant, without a waiver of the thimerosal ban, these groups could not be vaccinated.

There is no scientific evidence that thimerosal in vaccines poses any risk to children,  pregnant women, or their fetuses. In fact, the evidence contradicts the claims by the anti-vaccine lobby that thimerosal in vaccines is a cause of autism. On a multitude of levels there is ample reason to reject any link between thimerosal and autism:

1. All of the legitimate studies to date have failed to demonstrate any link.

2. The apparent increase in autism cases has continued even after the removal of thimerosal from vaccines.

3. Finally, and a usually neglected part of the story, the kind of mercury contained in thimerosal (ethylmercury) is very different from the kind produced by industrial pollution, and that ends up in the fish you eat (methylmercury). While methylmercury becomes concentrated in the body’s tissues (most importantly the brain) and thus remains for prolonged periods, ethylmercury is much more rapidly eliminated, and is therefore much less readily stored by the body. Recent studies have demonstrated just how different the pharmacokinetic properties of these two types of mercury are in the bodies of infants. This is important when we consider the US EPA “reference dose” (RfD) for mercury. This is the upper level daily amount, over a lifetime, of a substance that is considered safe to the most sensitive individuals in a population. The RfD for mercury set by the EPA is 0.1 micrograms per kilogram of body weight per day. Many people who believe the thimerosal-autism link point to the fact that, before thimerosal was removed from vaccines, some infants received a total daily dose of mercury from vaccines that came close to or exceeded the EPA’s RfD for mercury. Keep in mind, however, that the RfD was based on long-term, life-time daily exposures, not one time or even multiple time exposures. Also, as a safety factor the RfD was set 10 times higher than the actual estimated safe level. But most importantly, the RfD for mercury is based on data for methylmercury, not ethylmercury. That is, all the assumptions about the hypothetical dangers of exceeding the RfD for mercury, on potentially a few occasions, are based on an RfD for the wrong kind of mercury. As discussed above, the data on the pharmacokinetics of ethylmercury suggests a very different, and far less concerning picture for thimerosal in vaccines.

But let’s return to the legislation at hand. Besides their inclusion under this thimerosal ban, what else is exceptional about pregnant women and children under the age of 3? Well, they happen to be at greatest risk for serious complications of H1N1 disease, and are considered to be the highest priority populations for receipt of the vaccine. So, ironically, those at greatest risk for severe morbidity and mortality from the disease, and who are at the top of the list for getting the vaccine, aren’t permitted by law to receive it. Until, that is, states began issuing emergency waivers of these absurd laws.

To be fair, written into the law is a provision for the Comissioner of Public Health to waive the law during times of vaccine shortage or in the event of a severe outbreak. The important point, however, is what the very existence of these laws reveals about the power of the anti-vaccine lobby and a fear-stoked constituency. The fact that 7 states have enacted laws banning thimerosal-containing vaccines, and that there is similar legislative activity occuring in several other states, is a testament to the power of fear over reason, and the struggle of science to gain a foothold in our national consciousness. Although California has also temporarily waived their thimerosal ban, California’s secretary of Health and Human Services, Kim Belshe, issued this dark-aged rejoinder,

We take very seriously the expressed concerns that mercury in vaccines causes autism and remain committed to full implementation of [the law]

One of the greatest dangers of this trend away from a scientific view of medicine, and toward a more individualistic or even democratic one, is the solidification of this group think into the bedrock of legislation. The legislative process, shaped by constituencies, lobbies, and the personal leanings and beliefs of legislators, is frighteningly susceptible to irrational and anti-scientific forces. Glaring examples of this can be seen in the enactment of the Dietary Supplement Health and Education Act of 1994, the formation of the National Center for Complementary and Alternative Medicine in 1998, the establishment of Title V, Section 510 of the Personal Responsibility and Work Opportunity Reconcilitation Act (A.K.A. abstinence only education) in 1996, and the numerous insurance equality laws most states have enacted to mandate insurance coverage of chiropractic treatemnts, and other so-called “CAM” providers. This last type of legislation is particularly concerning. The newly formed Institute for Science in Medicine is currently working to address stealth provisions in health care reform legislation, now being debated in the Senate, that seek to legitimize “CAM” practitioners and mandate insurance coverage for a wide array of medically invalidated treatments. If this legislation is passed, more anti-science will be foisted upon our nation’s system of health care.

A quote from the recent New York Times review of Michael Specter’s new book, “Denialism“, sums up this trend toward “giving the people what they want” in health care. Although democracy is a wonderful way to run a nation, it isn’t how we develop science-based medicine.

…for better or worse, people are more skeptical of authority than they used to be and want to think for themselves, which includes grappling with the minutiae of science. Not so long ago, for example, patients rarely questioned doctors before undergoing surgery or taking their pills (for example, estrogen replacement therapy to prevent heart attacks), a blind obedience to authority that arguably cost many more lives than, say, vaccine refusal does now. What we are seeing is the democratization of science…

Give the people what they want, damn the evidence.


Posted by John Snyder

John Snyder, MD, FAAP, is an Assistant Professor of Pediatrics at Tufts University School of Medicine, and a practicing pediatrician at Amherst Pediatrics in Amherst, Massachusetts. Previously, he was Medical Director of the teaching clinic at Baystate Children's Hospital, and before that he was Chief of the Section of General Pediatrics and Medical Director of Pediatric Ambulatory Care at Saint Vincent's Hospital in New York City. Since 1994, Dr Snyder has been active in pediatric resident and medical student education with a particular interest in evidence-based pediatrics. His main area of interest is medical myth and the ways in which parents utilize information in making medical decisions for their children. One area of focus has been the vaccine myth, and he lectures frequently on this subject in both academic and community settings. His other activities have included: contributor to the Gotham Skeptic blog, member of the New York City Skeptics' board of advisors, and expert for ("A New Social Network on Health Founded by America's Top Doctors"). Dr Snyder graduated from Mount Sinai School of Medicine, completing his residency training in pediatrics at The Mount Sinai Hospital in New York City. He is board certified in pediatrics, and is a Fellow of The American Academy of Pediatrics. Dr. Snyder has no ties to industry, and no conflicts of interest regarding any of his writings. Dr. Snyder’s posts for Science-Based Medicine are archived here.