Are you "vaccine hesitant"? You may be in a cult

Edward Jenner, who pioneered vaccination, and two colleagues
 (right) seeing off three anti-vaccination opponents, with the dead
lying at their feet (1808). I Cruikshank/Wellcome Images/Wikimedia
Commons, CC BY-SA

The World Health Organization recently declared that "vaccine hesitancy," as they called it, was one of the top 10 threats to global health. That's right: it was up there with air pollution, climate change, influenza, Ebola, and other threats.

For the WHO, "vaccine hesitancy" is a polite phrase designed to engage the public and highlight how serious the problem is, without angering those who are guilty of it. I'm not going to be quite so polite here: "vaccine hesitant" means anti-vax. The anti-vax movement, which aggressively spreads fear and misinformation about vaccines, has become a major, worldwide threat.

It also resembles a cult, as I'll explain.

The most recent anti-vax nonsense centers on the new coronavirus that originated in China, and that has led the Chinese government to impose a massive quarantine affecting millions of people. This is a genuine public health crisis, and it has nothing to do with vaccines. Nonetheless, some anti-vaxxers are claiming, without evidence, that the new virus originated from a failed effort to create a coronavirus vaccine. I don't have time to get into that here, but Orac has a lengthy, detailed takedown of that bogus claim.

"Vaccine hesitancy" sometimes refers to parents who are just learning about vaccines for the first time, and who rely on the Internet to search for information. Unfortunately, these new parents are likely to be flooded with anti-vax messages, especially on Facebook. (In recent years, Google has taken steps to lower the priority of anti-vax sites, which has improved things considerably. Sites such as healthychildren.org now appear near the top of searches for "vaccine safety.") It's entirely reasonable to ask your doctor about the benefits and risks of vaccines.

But the answers that parents hear should be clear: vaccines work. As physician ZDoggMD (a pseudonym, obviously) explains in this video:

"Anti-vaccine sentiment is a poisonous scourge.... There's no debate about vaccines. Let's get over that nonsense that the media and celebrities have created, okay? There is nobody in the medical community of any actual reputation who believes that there are two sides to this."

The problem is that anti-vaxxers are continuously creating new websites, Facebook groups, and even movies to spread misinformation about vaccines, particularly the long-debunked claim that vaccines cause autism.

Why do I suggest that anti-vaxxers resemble a cult? Because they have several of the key features of cults, such as:

1. Members of the cult have special insights that outsiders cannot comprehend. With anti-vaxxers, this means they are completely convinced that they know that vaccines cause harm, despite mountains of evidence to the contrary.
2. The group and its leaders are the exclusive means of knowing "truth" or receiving validation, and no other process of discovery is credible. The anti-vax movement has had several prominent leaders, whose followers flock to their speeches and events. These include Andrew Wakefield, the disgraced former doctor who lost his medical license after it was revealed that he had committed fraud. His followers, though, either don't know or ignore his fraudulent past, and regard him as a hero. He makes a living from his books, a movie, and speaking fees, all based on spreading fear about vaccines. An even more prominent anti-vax leader is Robert Kennedy, Jr., who also sells books and gives speeches proclaiming the harms of vaccines. Thanks to his famous name, and despite the fact that he has no medical or scientific training, some people believe him.
3. Unreasonable fear about the outside world, such as impending catastrophe, evil conspiracies and persecutions. Conspiracy theories are the core of many anti-vax arguments. The most common version holds that the "medical establishment" (whoever that is) are hiding the dangers of vaccines so that they can make money. This is utter nonsense. All of doctors I know in the infectious disease community are motivated by a wish to cure disease. In any case, most doctors make little or no money from the vaccines they administer.
4. No meaningful financial disclosure regarding budget or expenses. Some anti-vaxxers profit handsomely by selling bogus, ineffective supplements as alternatives to vaccines. (I'm looking at you, Joe Mercola.) Because supplements are largely unregulated, they get away with it. They'd prefer you to think they're "just in it for the children."

I've no doubt that anti-vaxxers like Wakefield, Kennedy, and others would deny that they are conspiracy theorists, because that's how conspiracy theorists operate. If you question them (they argue), you must be part of the conspiracy. By their own reasoning, they can never be wrong.

So if you encounter someone, either on the sidelines at your kid's soccer game, on Facebook, or elsewhere, who is spreading claims that vaccines are harmful, pause for a minute and ask: what is the source of this information? Is it coming from someone who is profiting from this fear-mongering? There's a good chance the answer is yes.

It's ironic that when the world is faced with a true health emergency, such as the Ebola virus or the Wuhan coronavirus, the first thing that public health experts start to work on is a new vaccine. That's because vaccines provide our best protection against infections. We now have effective vaccines for 16 diseases that used to harm and even kill children in large numbers around the world. We've eliminated smallpox worldwide, and we've nearly eliminated polio, thanks to vaccines. Their very effectiveness is what has allowed the anti-vax message to take hold: many people are no longer frightened of dying from infectious diseases.

We're still a long way from conquering infections, but there's no reason for the world to slip back in time to an era when large numbers of people died from preventable infections. Vaccines work, if we'll let them.

Anti-vaxxers are to blame for a new epidemic of measles in the U.S.

Measles is now spreading outward from Disneyland in California, in the worst outbreak in years. The epidemic is fueled by growing enclaves of unvaccinated people. 

The CDC reports that in just the past month, 84 people from 14 states contracted measles, a number that is certainly an under-estimate, because the CDC doesn’t record every case. California alone has 59 confirmed cases, most of them linked to an initial exposure in Disneyland. A majority of people who have gotten sick were not vaccinated.

For years, scientists (including me) have warned that the anti-vaccination movement was going to cause epidemics of disease. Two years ago I wrote that the anti-vaccine movement had caused the worst whooping cough epidemic in 70 years. And now it’s happening with measles.

Finally, though, the public seems to be pushing back. Parents are starting to wake up to the danger that the anti-vax movement represents to their children and themselves. 

What's sad about this – tragic, really – is that we eliminated measles from the U.S. in the year 2000, thanks to the measles vaccine. As this CDC graph shows, we've had fewer than 100 cases every year since. 

But we had 644 cases in 27 states in 2014, the most in 20 years. And 2015 is already on track to be worse. Measles may become endemic in the U.S, circulating continually, thanks to the increasing numbers of unvaccinated people. Until now, each outbreak was caused by someone traveling from abroad and bringing measles to us. The anti-vaccine movement has turned this public health victory into defeat.

Anti-vaxxers have been relentless in the efforts to spread misinformation. Despite overwhelming scientific evidence that vaccines are beneficial, they endlessly repeat a variety false claims, such as

• Vaccines cause autism. They don’t.
• The preservative thimerosal in vaccines causes autism. It doesn’t.
• Natural immunity is all you need. It isn’t. Measles infects 90% of people exposed to it unless they are vaccinated.
• A healthy lifestyle will protect you from measles. It won’t.

Now, finally, some parents are pushing back. Parents and schools in California, where the epidemic began, are concerned that their children will be exposed to measles from unvaccinated children in schools. And the schools are starting to do something they should have done long ago: send the unvaccinated kids home.

The problem arises from California’s vaccine exemption policy: although public schools require kids to be vaccinated, parents can exempt their kids simply by saying they have a personal objection to vaccination. It’s not just California: only two states, Mississippi and West Virginia, don’t allow parents to claim a philosophical or religious exemption to vaccines  And Colorado has the worst rate of vaccination, at just 82%, primarily due to parents claiming a “philosophical” exemption.

These parents are the anti-vaxxers. Thanks to them, we now have large pockets of unvaccinated children through whom epidemics can spread further an faster than we’ve seen in decades. The CDC reports that in 2014, 79% of measles cases in the U.S. involving unvaccinated people were the result of personal belief exemptions.

Anti-vaxxers don't recognize the threat their behavior poses to others, especially to children whose immune systems aren’t functioning properly. CNN reported this week on the case of Rhett Krawitt, a 6-year-old California boy who has gone through 4 years of chemotherapy for childhood leukemia. His leukemia is in remission and he’s back in school, but the treatment wiped out his immunity, and he’s still not ready to get vaccinated. If Rhett gets measles, he might not survive. His father Carl wrote to school district officials to ask them to ban unvaccinated children from school.

Krawitt expects the schools to deny his request.

Meanwhile, the parents who refuse to vaccinate their kids aren’t budging. The New York Times reported on one mother, Crystal McDonald, who refused to vaccinate any of her four children, after “researching the issue” by reading anti-vaccine websites. When their high school sent her daughter home for two weeks, the daughter asked if she could get the measles shot so she could return. As quoted in the Times, McDonald told her daughter “I said ‘No, absolutely not.’ I said I’d rather you miss an entire semester than you get the shot.’”

Where does this breathtaking science denialism come from? It’s been building for years, as I and many others have written. The wave began with a 1998 paper published in The Lancet by Andrew Wakefield, claiming that the MMR vaccine was linked to autism. Wakefield’s work was later shown to be fraudulent, and his claims about the vaccine "dishonest and irresponsible." After lengthy investigations, the paper was retracted and Wakefield lost his medical license. Despite this very public repudiation, Wakefield has stuck to his claims, though, and has spent much of the past 15 years speaking (or perhaps “preaching” would be a better term) to anti-vaccine groups, to whom he is a kind of folk hero.

It’s not just Wakefield, though. Anti-vaccine messages have been broadcast aggressively by the group Generation Rescue, led by former Playboy playmate and MTV host Jenny McCarthy, and by Age of Autism, a group dedicated to the proposition that vaccines cause autism. (Age of Autism is doing it again right now.) And just last summer, Robert F. Kennedy Jr. published a new book further promoting the long-discredited claim that thimerosal causes autism. 

Most of the anti-vax crowd have no scientific training or expertise, which might explain (but doesn't excuse) their complete ignorance of the science. Over the past 15 years, dozens of studies involving hundreds of thousands of people have shown convincingly that neither vaccines nor any of the ingredients in them are linked to autism. Vaccines are not only safe, but they are perhaps the greatest public health success in the history of civilization.

Measles, though, is dangerous. The CDC’s Anne Schuchat had a message for parents this week:

“I want to make sure that parents who think that measles is gone and haven't made sure that they or their children are vaccinated are aware that measles is still around and it can be serious. And that MMR vaccine is safe and effective and highly recommended.”

Make no mistake, measles is a very dangerous infection. In the current outbreak, 25% of victims have ended up in the hospital. And it is extremely infectious: the CDC’s Schuchat explained that 

“You can catch it [measles] just by being in the same room as a person with measles even if that person left the room because the virus can hang around for a couple of hours.”

Perhaps the Disneyland epidemic, which has now spread to 14 states, will finally convince parents, schools, and state legislatures that they need to insist that children get vaccinated before going to school. Perhaps it will also convince parents to stop listening to nonsense, and choose wisely by getting their children vaccinated against measles. We won this battle before, and we can win it again.

“Shocking Report” on flu vaccines is neither shocking nor correct

Flu season is coming, and once again it’s time to get your flu shot (or snort, if you prefer FluMist). It’s not perfect, but the vaccine is your best protection against the influenza virus.

So I was surprised to stumble upon an article titled “Johns Hopkins Scientist Reveals Shocking Report on Flu Vaccines,” which popped up on an anti-vaccine website two weeks ago. Johns Hopkins University is my own institution, and I hadn’t heard any shocking new findings. I soon discovered that this article contained only a tiny seed of truth, surrounded by a mountain of anti-vaccine misinformation. Most of it focused on a report published in early 2013 by Peter Doshi, a former postdoctoral fellow at Hopkins.

First, as Snopes.com has already pointed out, Doshi is not a virologist or an epidemiologist, but rather an anthropologist who studies comparative effectiveness research. He never conducted influenza research at Hopkins. (He’s now an Assistant Professor at the University of Maryland’s School of Pharmacy.) Second, Doshi’s 2013 article was an opinion piece (a “feature”), not an original research article, and it did not report any new findings. Third, it is highly misleading to suggest (as the anti-vax article’s title does) that Doshi somehow represents Johns Hopkins University. At Johns Hopkins Hospital, the flu vaccine is required of all personnel who have contact with patients, as a good-practices effort to minimize the risk that a patient will catch the flu from a caregiver.

But what did Doshi’s article say? Even though it isn’t new, why are the anti-vaccine sites recycling it? His central argument is this:

“The vaccine might be less beneficial and less safe than has been claimed, and the threat of influenza appears overstated.”

Let’s look at this statement. It’s almost obviously true: one only has to find a few overstated claims about the risks of flu, which isn't hard to do. But it’s also completely consistent to state that the vaccine is enormously beneficial and that the threat of influenza is very serious. See how that works? 

Doshi uses this slight-of-hand to suggest that the vaccine may not be beneficial at all. He never says this outright—instead, he just questions, again and again, whether the precise percentages reported in published studies are accurate. For example, he makes a big deal of a CDC announcement in 2013 that the vaccine’s effectiveness was only 62%. He casts doubt with phrases like 

“the 62% reduction statistic almost certainly does not hold true for all subpopulations”

which is almost certainly true, but is meaningless from the point of view of public health. Of course the vaccine doesn’t have the same effectiveness in everyone. The point is that it works most of the time. 

Doshi cites another study that showed a clear benefit for the flu vaccine, only to cast doubt on it with this argument: 

“No evidence exists, however, to show that this reduction in risk of symptomatic influenza for a specific population—here, among healthy adults—extrapolates into any reduced risk of serious complications from influenza such as hospitalizations or death in another population.”

Again, Doshi’s argument doesn’t prove that the original study was wrong, only that it doesn’t apply to everyone. But Doshi’s motivation, as evidenced by the relentlessly negative slant of his entire article, seems to be to convince people that the flu vaccine is bad.

Not surprisingly, the anti-vaccine movement has embraced Doshi (for example, here and here). And unfortunately, he seems to have accepted their acclaim: in 2009, he spoke at an anti-vaccine conference hosted by NVIC, a notorious (and misleadingly named) anti-vaccination group.

Perhaps even more disturbing is that Doshi signed a petition arguing that the HIV virus is not the cause of AIDS, joining the ranks of HIV denialists. He signed this statement while still a graduate student, so I contacted him to ask if he still doubted the link between HIV and AIDS. I also asked him if he supports flu vaccination, if he agrees with the anti-vaccine movement's use of his statements, and if he believes the flu is a serious public health threat.

On the question of signing the HIV/AIDS petition, Doshi responded that "Seeing how my name was published and people have misconstrued this as some kind of endorsement, I have written the list owner and asked for my name to be removed." (He declined to state directly - and I gave him the chance - that he agrees that the HIV virus causes AIDS.)

As for the flu itself, Doshi says "I don’t agree with CDC’s portrayal of influenza as a major public health threat." So he and I have a serious disagreement there. I asked if he agrees with the anti-vaccinationist who are using his writings to claim that the flu vaccine is ineffective, and he replied that while "ineffective" is "too sweeping," he has found "no compelling evidence of hospitalization and mortality reduction in [the] elderly."

Doshi’s argument against the flu vaccine boils down to this: the vaccine is much less than 100% effective. This is undeniably true, and the research community makes no secret of it. In fact, many of us have repeatedly called for more research into better vaccines, in the effort to create a vaccine that is not only more effective, but that (like most other vaccines) only needs to be taken once for lifetime immunity. We’re just not there yet. Meanwhile, though, the annual flu vaccine is usually effective: a recent study showed, for example, that it reduced children’s risk of ending up in a pediatric intensive care unit by 74%.

So get your flu shot (or snort) now, before flu season hits, because it takes a couple of weeks for your body to develop immunity. By getting immunized, you’ll not only increase your chances of getting through the winter flu-free, but (because you won’t spread the flu to others) you might also save someone whose immune system would be overwhelmed by influenza. 

Cashing in on fears of autism

Autism has been the subject of much controversy in recent years.  Rates of diagnosis are rising, and many parents-to-be are understandably worried.  Despite the efforts of many good scientists, we still don't have an explanation for most cases, although we do know that vaccines have nothing to do with it. Many unscientific claims are out there, some of them designed to take advantage of vulnerable parents who are desperate for answers. In this climate, any new claim to have found "the" cause of autism ought to be stated very, very carefully, and backed up by solid evidence.

Just recently, scientists at the UC Davis Mind Institute published a study that described 6 antibodies found in the blood of some mothers of autistic children, and much less often found in mothers of normally developing children.  They suggested that these antibodies somehow got into the brains of developing fetuses, causing autism in the children.  They even gave a name to this form of autism: maternal autoantibody-related, or MAR autism.

If true, this study suggests that a test for these antibodies might predict whether or not a child will have autism.

The study seems plausible, and it was published in a respectable journal called Translational Psychiatry.  Unfortunately, though, the study and the way it has been promoted are plagued with problems.

Perhaps the biggest red flag is that the two lead authors, Daniel Braunschweig and Judy Van de Water already have a patent on the proteins described in their paper, and Van de Water is involved with a company, Pediatric Biosciences (PBI), that is already marketing a test to predict autism based on this study.  Van de Water is the Chief Scientific Advisor for the company, which has licensed her patent for this specific test.  The company website claims

"To date, the test has demonstrated 100% accuracy - meaning if a mother or prospective mother has developed the antibodies, then her child will later be diagnosed with AU [autism] or ASD [autism spectrum disorder]."

Wow. This sounds incredibly accurate. This test is apparently the sole product of PBI, and they trumpeted the new study with a press release claiming that

"PBI is developing a diagnostic test based on these findings that will provide physicians with a reliable set of biomarkers for pre-conception … diagnosis of this Maternal Autoantibody-Related (MAR) form of autism."  

PBI is marketing the test to all "women over 30 who are at least 2 times more likely to give birth to an autistic child" as well as other women.

So, with all this hype, and despite the major conflicts of interest of the lead authors, did the study show what they are claiming?  Is this a test that mothers should take?

In a word, no.

First, the study doesn't even answer the right question.  The study looked at antibodies found in the blood of mothers some years after their pregnancy, not during or before pregnancy. Therefore it doesn't tell us whether a test of a pregnant mother will predict anything at all.  Post hoc analyses like this are notoriously inaccurate: for example, it's easy to find factors that predict every presidential election for the past 50 years, but many of them will perform poorly at predicting future elections.  Similarly, finding 6 proteins that distinguish some mothers of autistic children from mothers of normal children, all measured after the fact, tells us nothing about whether we can predict autism in advance.

Second, their striking claim of 100% accuracy is false.  (Their press release only claimed 99%: "A positive result would mean that they have a 99 percent likelihood of having a child with autism if they proceed with a pregnancy.")  But the study provides no such evidence.  What it did show was that 56 mothers (out of 246) had antigens to one of 12 combinations of 3 antigens that they selected.  [Aside: there are many other combinations of antigens that they did not report, and no indication that they properly adjusted their statistics to account for this.] But the study failed to say whether these 56 mothers also had non-autistic children.  If they did, then even the mothers in their own study had a much lower chance than 99% of having an autistic child.  Given that many families with autistic children also have other, non-autistic children, touting an accuracy number like this, without proof, is outrageous.

The study isn't completely worthless: it points to a possible link between antibodies in the blood of the mother and autism in a child.  If Van de Water were truly interested in the welfare of autistic families, she would be focusing on the obvious next step: test a large, randomly sampled collection of pregnant women for the same antibodies.  Then follow them up, over the next few years, to see if the test can predict the likelihood of having an autistic child.  Meanwhile, no one should be selling a test before studies can show that it has some predictive value.

But Van de Water and her friends at Pediatric Biosciences seem far more interested in making money off the fears of prospective parents.  PBI is planning to charge about $800 for their test, which they'll begin selling next year. Stanford University biostatistician Steven Goodman says that they are "peddling false hope that giving birth to autistic kids can be avoided."

A news article in Science last week raised many serious questions about Van de Water's study and its claims.  Several scientists quoted in that article questioned the premise of the study: that antibodies from the mother somehow get into the brain of the developing fetus. Yale scientist George Anderson said the data are too preliminary and the statistics too weak to support a clinical test (essentially the same argument I'm making here).

And what about that 99% claim?  In their interview with Science, Van de Water and Jan D'Alvise (president of PBI) said it

"was not meant to convey likelihood in the statistical sense, but rather the 99% accuracy with which the study demonstrated specificity of the biomarkers for ASD."  

This is unadulterated poppycock. As of this writing, the company website still claims that the test has "100% accuracy--meaning if a mother or prospective mother has developed the antibodies, then her child will later be diagnosed with AU or ASD [autism]."  That claim couldn't be any more clear - or any more wrong.

With all the controversy over the causes of autism, and with the medical community still struggling to correct the tremendous damage caused by Andrew Wakefield's fraudulent study linking vaccines to autism, the last thing we need is an erroneous claim that someone has found the cause of autism.  And it's far too soon to start offering moms a test that tells them they're going to have an autistic child.

IOM to Public: Childhood Vaccine Schedule is Safe

Hey parents: if you've been taken in by anti-vaccine discussions on the internet, you might want to look at the newest report from the Institute of Medicine.  After a lengthy and thorough review of the evidence, the IOM issued a report last week that found that the current childhood immunization schedule in the United States is safe.

The IOM committee specifically looked for evidence that vaccination is linked to "autoimmune diseases, asthma, hypersensitivity, seizures, child developmental disorders, learning or developmental disorders, or attention deficit or disruptive disorders", including autism.  Their finding: no evidence suggests a link to any of these conditions.

The motivation for the report is the growing incidence of parents who worry that there are "too many, too soon" - a catchphrase that was the basis of an anti-vaccine campaign led by Generation Rescue and its spokesmodel, Jenny McCarthy.  This concern, which sounds reasonable on its face, never had any evidence to support it.

Anti-vaccine activists have pointed out, correctly, that the number of vaccines has increased significantly over the past several decades.  The current schedule has as many as 24 immunizations in a child's first two years, and up to five injections in a single visit.  The reason for this is simple: the scientific community has developed vaccines against a growing number of childhood illnesses.  As a result, many diseases that used to infect millions of children each year, killing or permanently injuring thousands of infants and toddlers, have almost disappeared from modern societies.  This is a good thing.

Many parents have been convinced to "slow down" vaccines after hearing advice from self-proclaimed vaccination authorities, such as "Dr. Bob" Sears.  Sears has published his own alternative vaccine schedule (which he apparently just made up - he certainly didn't do a scientific study) and whose has gotten rich selling his book and offering other advice.  Journalist Seth Mnookin calls Sears "a first-rate huckster."

Noted vaccine expert Paul Offit, in a peer-reviewed article in the journal Pediatrics four years ago, explained how Sears ignores all the science on vaccine safety, sometimes simply replacing objective evidence with his own "facts." Offit also called out Sears for his advising parents not to vaccinate their kids, but then not to tell their neighbors:

“I also warn [parents] not to share their fears with their neighbors, because if too many people avoid the MMR, we'll likely see the diseases increase significantly.” [wrote "Dr. Bob" Sears]  

In this astonishingly selfish comment, Sears admits that herd immunity works, but then says don't tell your neighbors, because then their kids might get sick and infect your unvaccinated kids.

Offit's article is a thorough, point-by-point rebuttal of Sears' numerous claims, many of them either misleading or downright false.  I highly recommend it.  Or  read the IOM's report online, for free.  Don't waste your money on Dr. Bob's book.

Let's hope all parents will follow the recommended vaccine schedule and ignore the voices of fear and unreason who are trying to scare them.  If you're still in doubt, read the heartbreaking story, from just a few days ago, of 7-year-old Alijah Williams in New Zealand.  Alijah's well-educated parents thought they were doing the right thing by withholding vaccines, after reading some scary material on the internet.  Alijah was infected with tetanus last year and fought it for months, nearly dying in the process.  His recovery will take 12 months, during which he will have to re-learn how to eat and walk on his own.  His parents have now become activists trying to spread the word among their community that infections are the real threat - not vaccines.

Congress holds an anti-vaccine hearing

I was in my car yesterday listening to C-SPAN (yes, I do that sometimes), when to my stunned surprise I heard Congressman Dan Burton launch into a diatribe on how mercury in vaccines causes autism.  No, this was not a replay of a recording from a decade ago.  The hearing was held just a few days ago by the Committee on Oversight and Government Reform.

Congressman Burton used this hearing to rehash a series of some of the most thoroughly discredited anti-vaccine positions of the past decade.  Burton is a firm believer in the myth that vaccines cause autism, and he arrogantly holds the position that he knows the truth better than the thousands of scientists who have spent much of the past decade doing real science that proves him wrong.  

In a classic political move, the committee called on scientists Alan Guttmacher from the NIH and Colleen Boyle from the CDC to testify, but in fact the committee just wanted to bully the scientists.  Committee members lectured the scientists, throwing out bad science claims, often disguised as questions, thick and fast.  Alas, Guttmacher and Boyle weren't prepared for this kind of rapid-fire assault by pseudoscience.

Burton himself was the worst offender, offering anecdotes and bad science with an air of authority.  He stated bluntly: 

“I’m convinced that the mercury in vaccinations is a contributing factor to neurological diseases such as autism."

No, it isn't.  Dozens of studies, involving hundreds of thousands of children, have found the same thing: there is no link whatsoever between thimerosal and autism, or between vaccines and autism.  And Burton went off the deep end with this: 

"It wasn’t so bad when a child gets one or two or three vaccines… Mercury accumulates in the brain until it has to be chelated.” 

Bang bang, two false claims in 10 seconds.  First he claims that mercury from vaccines "accumulates in the brain", a statement with no scientific support at all. Then he claims that chelation therapy is the solution - a radical, potentially very harmful treatment that no sensible parent would ever force on their child.  Unfortunately, some quack doctors have experimented with chelation therapy on autistic children, despite that fact that it can cause deadly liver and kidney damage, and one of them caused the death of a 5-year-old boy in 2005.

Burton also claimed that single-shot vials would "eliminate the possibilty of neurological damage from vaccines" - a claim that was invented out of thin air by the discredited anti-vax doctor Andrew Wakefield, whose fraudulent 1998 study was the spark that started the current wave of anti-vax hysteria.

Congressman Bill Posey from Florida was just as bad as Burton, demanding a study of vaccinated versus unvaccinated children, a standard talking point of the anti-vax movement.  (Congressman Posey: do you even realize that your question is almost identical to what Jenny McCarthy asked five years ago, on the Larry King Live show?)  Here's his question to the CDC's Boyle:

"I wonder if the CDC has conducted or facilitated a study comparing vaccinated children with unvaccinated children yet - have you done that?"

Dr. Boyle wasn't prepared for this.  She tried to point out that many studies have been done looking at the relation between vaccines and autism, but she didn't get very far before interrupted, thus: 

Rep. Posey: “So clearly, definitely, unequivocally, you have studied vaccinated versus unvaccinated?” 

Dr. Boyle: “We have not studied vaccinated versus unvaccinated." 

Posey: “Never mind. Stop there. That was the meaning of my question. You wasted two minutes of my time."

Dr. Boyle simply wasn't prepared for a Congressman who was parroting anti-vax activists.  It's too late now, but her response should have been this:

Congressman Posey, only an extremely unethical scientist would consider conducting such a study.  To compare vaccinated versus unvaccinated children in the manner you suggest, one would have to withhold vaccines from young children.  We know from decades of evidence, involving tens of millions of children, that vaccines save lives.  Few if any medical interventions are more effective than vaccines. 

But Congressman, the scientific community has done observational studies of vaccinated versus unvaccinated children, comparing autism rates in children whose parents chose not to vaccinate.  Those studies show that autism rates were slightly higher in unvaccinated children.  That's right, vaccinated children had autism at a lower rate. 

So no, Congressman Posey, the CDC hasn't done a study of vaccinated versus unvaccinated children.  Only a corrupt dictatorship could impose a study like that on its people.  Is that what you want?

To make matters worse, the House committee invited Mark Blaxill to testify.  Blaxill is a well-known anti-vaccine activist whose organization, SafeMinds, seems to revolve around the bogus claim that mercury in vaccines causes autism.  His organization urges parents not to vaccinate their children, and giving him such a prominent platform only serves to spread misinformation among parents of young children.  

Blaxill's central claim is that that we're in the midst of an autism epidemic: 

"For a long time, reported U.S. autism rates were low, estimated at about 1 in 10,000. Then around 1990 something new and terrible happened to a generation of children. Autism rates didn’t just rise, they multiplied," claimed Blaxill in his written testimony.

His entire argument builds on this.  Yet multiple studies, looking carefully and objectively at the data, indicate that all or nearly all of the rise in autism cases is due to increasing diagnoses, which in turn is due to multiple factors: a dramatically broading of the definition of autism in the early 1990s, a greater awareness of the condition, and a greater willingness of doctors and parents to accept the diagnosis.  For an objective summary of the evidence, see the articles by neurologist Steven Novella here and here, which summarize a dozen epidemiological studies.  The weight of the evidence shows that the actual incidence of autism is either stable or possibly rising very slowly.  There is no "autism epidemic."

It's also worth pointing out that Blaxill is a conspiracy theorist who claims that the "CDC has actively covered up the evidence surrounding autism’s environmental causes."  

Congress has every right to conduct oversight into medical research at the NIH and the CDC.  But when Dan Burton, Bob Posey, and others decide in advance what the science says, and abuse their power to demand "answers" that validate their badly mistaken beliefs, people can be harmed. Over the past decade, the anti-vaccine movement has successfully convinced millions of parents to leave their kids unvaccinated, and the result has been serious outbreaks of whooping cough, haemophilus, measles, chicken pox, and mumps around the U.S. and Europe.  

Some anti-vax parents claim that these childhood illnesses aren't so bad.  I wish they would talk to the parents of young children who have died in recent whooping cough outbreaks.  These illnesses can be deadly.

Message to Congress: science isn't easy, and autism is complicated.  Don't criticize science when it doesn't give you the answer you thought you knew.  That's not how science works.  Thousands of scientists are now trying to identify the causes of autism, and they've made progress, especially on the genetic front.  The answer might not be simple, but we will find it.