As The Facts Win Out, Vaccinations May, Too Twenty-five percent of Americans believe vaccines could lead to development disorders in children. How can so many people be wrong?

As The Facts Win Out, Vaccinations May, Too

As The Facts Win Out, Vaccinations May, Too

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Vials of vaccines

Discredited vaccination researcher Andrew Wakefield was brought to a new low this week when a prominent British medical journal accused him of outright fraud.

Wakefield authored a 1998 study linking vaccines to autism -- a study that continues to fuel the anti-vaccination movement even as Wakefield's research is discredited by a growing number of sources.

Further research and accusations that Wakefield doctored results in his research have given new hope to those who would like to see the growing ranks of anti-vaccination parents start to shrink.

Seth Mnookin, a contributing editor at Vanity Fair and author of The Panic Virus, tells NPR's Guy Raz that might happen.

"The public health community and doctors are aware of the need to communicate more effectively," he says -- in a way they weren't several years ago.

The Panic Virus
The Panic Virus: A True Story of Medicine, Science, and Fear
By Seth Mnookin
Hardcover, 448 pages
Simon & Schuster
List price: $26.99
Read An Excerpt

A Cautionary Story

In April 2006, 3-year-old Matthew Lacek's sore throat turned into a near-death emergency. At the hospital, doctors thought it might be asthma, but their treatments weren’t working.

After several hours, a veteran pediatrician arrived. He looked at Matthew, then turned to the child's parents, Kelly and Dan Lacek.

"He said, 'Did you have your son vaccinated?'" Kelly remembers. They had not. "’If this is what I think it is, he doesn't have that much time to live,'" the doctor said.

Matthew had Hib, or haemophilus influenza type B, which can cause lethal swelling in the windpipe. The disease had been virtually wiped out since the introduction of a vaccine in the mid-1980s. But in 2003, the Laceks -- alarmed by growing autism rates and news reports that suggested a link to vaccinations -- had opted not to give the vaccination to their son.

After six days in the hospital on heavy doses of antibiotics and in a medically induced coma, Matthew woke up. Amazingly, he made a full recovery, with no lasting brain damage or developmental issues. Lacek still remembers what the doctor who made Matthew's initial diagnosis told her.

"'Please, do me a favor, and make a decision with your husband to get him vaccinated right away,'" the doctor told her. "He said, 'He's a one-in-a-million child who came out of this with nothing wrong with him."

Consequences of a Growing Movement

Hib and many other diseases thought to be eradicated have returned as more parents choose not to vaccinate their children.

Mnookin says diseases like whooping cough or pertussis have seen huge rises in cases across the country. Last year in California, there were more cases of whooping cough than at any point in half a century. Ten children died.

With children now at risk for diseases that were thought to be forgotten, "the risk of not getting vaccinated felt notional to a lot of parents," he says.

A 2010 pediatric study reveals the movement is growing. Twenty-five percent of parents believe vaccines could cause developmental problems in kids — a rise Mnookin blames, in part, on the media.

When the media puts celebrity and anti-vaccination advocate Jenny McCarthy alongside experts from the Center For Disease Control and Prevention, he says, it "gives the impression that there's an equal number of people on two sides of this.  And it's just not true."

Countering The Fears

"The American Academy of Pediatrics, the American Medical Association, the CDC, the EPA, doctors, scientists around the world all agree -- vaccines are safe," Mnookin says. That scientific consensus is now being trumpeted by a more communicative public health community.

Seth Mnookin is also the author of Feeding the Monster and Hard News. Sara James/ hide caption

toggle caption
Sara James/

Seth Mnookin is also the author of Feeding the Monster and Hard News.

Sara James/

"In pediatricians' offices, there are now, oftentimes, informational pamphlets," he says.

Seminars are held after hours for parents to discuss their concerns.

Additionally, he hopes parents become savvier researchers in the information age. Just Googling "vaccines" and "autism" is dangerous, he says. "There are reliable sources of information out there, and I think those are the people we should look to."
Mnookin recommends the websites of the CDC, American Academy of Pediatrics, and American Medical Association for reliable information about vaccine risks.

"There have been questions that were raised in the past that should have been -- and were -- examined. At this point, we're sort of at an asked-and-answered juncture of this debate."

Excerpt: 'The Panic Virus'

The Panic Virus
The Panic Virus: A True Story of Medicine, Science, and Fear
By Seth Mnookin
Hardcover, 448 pages
Simon & Schuster
List price: $26.99

On April 22, 2006, Kelly Lacek looked around her dinner table and smiled: Dan, her husband of thirteen years, was there, along with the couple's three children, Ashley, Stephen, and Matthew. Kelly's parents had also come over: There was a father-daughter dance at the local church that evening, and Kelly and her dad were double-dating with Dan and Ashley. As the four of them were getting ready to leave, Kelly couldn't resist needling her mother. "You're stuck with the boys," she said. "But don't worry -- we won't be out too late." She kissed Stephen goodbye, and then bent down to say good night to Matthew. He was three years old, and Kelly marveled at how quickly he was growing up: It seemed as if it was only moments ago that he'd been an infant, and now he was already being toilet-trained. (Dan and Kelly both agreed that it was adorable how proudly he announced that he had to go to the bathroom.)

For a brief moment, Kelly says, she wondered if Matthew was okay -- he seemed a little out of sorts, and earlier that afternoon, he'd complained of a sore throat -- but then she figured he'd probably just tired himself out wrestling with his older brother.

Kelly and Dan returned home that night around eight o'clock. They'd barely walked in the door when Kelly's mother rushed over: "It's Matthew," she said. "He's running a fever -- and his breathing seems a little shallow." The Laceks realized right away that something was seriously wrong. "He was just sort of hunched over," Kelly says. "We didn't know what to do." Since there was no way to get in touch with Matthew's doctor, they decided to make the ten-minute drive from their home in Monroeville, about fifteen miles east of Pittsburgh, to the Forbes Regional Campus of the Western Pennsylvania Hospital.

When the Laceks arrived at the emergency room, the attending physician told them there was nothing to worry about. In all likelihood, he said, Matthew had a case of strep throat. Worst-case scenario, it was asthma; regardless, they'd be home in no time. Two hours later, they were feeling much less assured: Matthew's fever was still rising, and when a doctor tried to swab his throat, he began to choke. By eleven p.m. Matthew's temperature had risen to 104 degrees and his breathing seemed to be growing shallower by the minute.

It was around that time that a doctor the Laceks hadn't met before walked over. He was older -- probably in his sixties, Kelly thought -- and as soon as he saw Matthew, he began to suck nervously on his teeth. He turned to the Laceks: Had Matthew received all his shots? Actually, Kelly said, he hadn't. Matthew had been born in March 2003, several years after rumors of a connection between autism and vaccines had begun to gain traction in suburban enclaves around the country. That May, Kelly's chiropractor warned her about the dangers of vaccines. "He asked if we were going to get [Matthew] vaccinated and I said yes," Kelly says. "And then he told me about mercury. He said, 'There's mercury in there.' " Kelly had already heard rumors that the combined measles-mumps-rubella (MMR) vaccine was dangerous, but this was something new. "He was really vocal about it causing autism. He said there was this big report over in Europe and blah blah blah. And I thought, Well, I'm surrounded by people who have autistic children. What if this happened to Matthew?" If Kelly was unconvinced, the chiropractor said, she should make Matthew's pediatrician prove to her that the vaccines Matthew was scheduled to receive were one hundred percent safe.

"So that's what I did," Kelly says. "I asked my doctor if she could give me a label that says there's no mercury and she said, 'No.' She said she wouldn't give it to me." It was as if, Kelly says, her pediatrician was hiding something. The doctor tried to tell Kelly that she would be putting Matthew at serious risk by not immunizing him, but, Kelly says, "I don't think I heard anything else she might have said, quite honestly. At that point I had lost faith."

From that day forward, Matthew didn't receive any of his scheduled vaccinations, including one for a bacterial disease called Haemophilus influenzae type b, or Hib. Oftentimes, a Hib infection is not particularly threatening -- if the germs stay in the nose and throat, it's likely the child won't get sick at all -- but if the infection travels into the lungs or the bloodstream, it can result in hearing loss or permanent brain damage. Hib can also cause severe swelling in the throat due to a condition called epiglottitis, which, if not treated immediately, results in infected tissue slowly sealing off the victim's windpipe until he suffocates to death. As recently as the 1970s, tens of thousands of children in America had severe Hib infections each year. Many of those suffered from bacterial meningitis, and between five hundred and one thousand died. After the Hib vaccine was put into widespread use, the disease all but disappeared in the United States: In 1980, approximately 1 in 1,000 children caught Hib; today, fewer than 1 in 100,000 do. In fact, the immunization had been so effective that out of everyone working in the Monroeville ER, the doctor who'd asked Kelly Lacek about her son's vaccine history was the only one who had been practicing long enough to have seen an actual Hib infection in a child.

Until that night, Kelly had never given much thought to the potential repercussions of her decision not to have Matthew vaccinated. "I must have read somewhere that after he turned three, he would have been okay for many of those diseases," she says. "I thought he was in the clear." She was wrong. "I have never seen a doctor panic so quickly," she says. If, as the doctor was all but certain was the case, Matthew had been infected, then everything that had been done to him in the hospital that night -- the examinations, the swabs, the breathing treatments -- had served only to further inflame his throat. It wasn't until Kelly saw her son's X-rays that she realized just how dire the situation was: It looked as if Matthew had a thumb lodged in his throat. "I started to shake," Kelly says. "There was just a tiny bit of airway left for him to breathe."

Within minutes, the entire emergency room was thrown into a frenzy. Kelly heard someone shout out, "Page Children's!" Then she heard a second command: "Get Life Flight here right away." Finally, a doctor pulled the Laceks aside and explained the situation to them. "If we don't get Matthew on a helicopter [to the Children's Hospital in Pittsburgh] right now, your son is probably going to die," he said. "It could be within minutes." While they were waiting, the doctor said, Kelly had to make sure Matthew remained calm. "I do not want you crying," the doctor said. "I do not want you reacting to anything. If you are upset, Matthew will be upset, and that will make his throat close up more. If that happens he will suffocate." As if in a daze, Kelly went and picked up her son. It wasn't until she heard her teeth chattering that she realized she was shaking. She focused all her energy on trying to remain still.

While Kelly was holding Matthew, Dan Lacek was conferring with the hospital staff. It had rained earlier in the evening, and now the entire area was covered in fog, which made it too dangerous to land a helicopter. Matthew was going to have to make the trip to Pittsburgh in an ambulance -- but before he could be moved, he'd have to be intubated. If that didn't work -- if there was not enough room in Matthew's throat for a breathing tube -- the doctors would try to perform a tracheotomy, which involves cutting into the windpipe in an effort to form an alternate pathway for air to get into the lungs. (The procedure is not without risk: The physicist Stephen Hawking lost his speech when the nerves that control the vocal cords were damaged during an emergency tracheotomy.) Once again, it fell to Kelly to keep her son calm. Fortunately, the tube slid down Matthew's throat. Unless it closed up so much that the tube was forced out, they'd bought themselves a few more hours.

It was almost four in the morning when the Laceks arrived in Pittsburgh. Matthew was immediately placed in a medically induced coma. All the doctors could promise was that he'd live through the night. "They said something about not catching it quickly enough with the antibiotics," Kelly says. "Even if he did recover, there was a good chance he would have permanent brain damage, or, best-case scenario, he would have hearing loss."

For forty-eight hours, Dan and Kelly Lacek's son remained in stable condition. "You're in shock," Kelly says. "You never let your guard down. You're just so focused on him getting better." Then, on Tuesday, just as they were growing more hopeful, Matthew's blood pressure plummeted. The only thing the Laceks could think to do at that point was to ask their friends to pray for them.

When Kelly Lacek's chiropractor told her that vaccines had been linked to autism, he was repeating the most recent of hundreds of years' worth of fears about vaccinations. The roots of this latest alarm dated back to 1998, when a British gastroenterologist named Andrew Wakefield claimed to have discovered a new gut disorder associated with the MMR vaccine -- and with autism. Wakefield based his conclusions on a case study of a dozen children who'd been brought to his clinic at the Royal Free Hospital in London. Almost immediately, Wakefield's research methods and his interpretations, which had been published in the medical journal The Lancet, came under fire. Wakefield's response was to appeal to the public rather than to his colleagues: The medical establishment was so determined to discredit him, he said, because he threatened their hegemony by taking parents' concerns seriously. The media took the bait, and despite Wakefield's lack of proof and his track record of dubious assertions and unverified lab results, they began churning out stories about how a maverick doctor was trying to protect innocent children from corrupt politicians and a rapacious pharmaceutical industry. Within months, vaccination rates across Western Europe began to fall.

Then, a year later, the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) publicly recommended the removal of a widely used mercury-based preservative called thimerosal from childhood shots. The move had been hotly debated; in the end, one of the factors that had tipped the balance was a concern that following the Wakefield brouhaha, any connection, real or rumored, between vaccines and neurodevelopmental disorders had a chance of unraveling public confidence in vaccines.

That fear proved to be well founded, in no small part because of the growing hold autism had on the public's consciousness. In the half-century since "infantile autism" had been defined as a discrete medical condition, it had gone from being a source of shame for parents, who were blamed for their children's conditions, to becoming a seemingly omnipresent concern, especially among those well-educated, upper-middle-class families for whom child rearing had become an all-encompassing obsession.

In spite of this increased attention, researchers in the 1990s were barely any closer to understanding autism's origins or devising effective therapies for its treatment than their predecessors had been fifty years earlier. For parents of autistic children, this lack of reliable information resulted in feelings of hopelessness and frustration; for parents in general trying to determine the best course of action for the future, it fueled a sense that medical experts and health authorities couldn't be counted on to look out for their families' well-being.

Together, these reactions prepared the ground for new hypotheses to take root, regardless of how speculative or scientifically dubious they were. In the year following the CDC/AAP recommendations regarding thimerosal, a small group of parents decided that some of the symptoms of mercury poisoning seemed to match the behavior they saw in their autistic children -- and they suddenly realized that their children had appeared to be fine before they'd received their vaccines. These parents began posting their observations online, sparking hundreds more parents to confirm that they'd noticed the exact same thing. With a network of nontraditional doctors and alternative health practitioners urging them on, they became more and more convinced that the common threads that ran through their stories were too odd and too widespread to be mere happenstance.

The more these newly politicized parents learned, the more outraged they became. Why were children with weak immune systems injected with vaccines just as potent as those used on children in perfect health? Why was everyone instructed to receive the same number of inoculations, regardless of their medical histories or family backgrounds? Why, for that matter, were more and more shots being added all the time? Was a chicken pox vaccine really necessary? Or one for the flu?

Just as had been the case with the MMR vaccine, there was no concrete evidence linking thimerosal to autism, and the anecdotal corroboration often seemed more impressive than it actually was. (To take but one example: Despite superficial similarities, the motor difficulties exhibited by people with mercury poisoning bear little resemblance to the repetitive movements typical of autistics.) That didn't stop the American media from reacting much the same way their colleagues across the Atlantic had when Andrew Wakefield had published his assertions, as the emotional pull of stories featuring sick children and devoted parents outstripped anything as boring as hard data or the precautionary principle. In a matter of months, an ad hoc coalition of "Mercury Moms" transformed itself into a potent political force: Senators spoke at their rallies, public health officials tried to assuage their concerns, and federal agencies included them in discussions on how to spend tens of millions of dollars. Soon, vaccination rates began to fall in the United States as well.

By the beginning of the new millennium, Wakefield's supporters and the proponents of the thimerosal link had joined forces to create an international cadre of vaccine skeptics whose message had an undeniable appeal: Parents trying to do nothing so much as raise their children had been taken advantage of by a society they had trusted -- and now they were determined to make it right.


Over the past two decades, the instant accessibility of information has dramatically reshaped our relationship to the world of knowledge. Five hundred years after Gutenberg's introduction of the printing press and Martin Luther's translation of the Bible let common people bypass the priestly class, the vernacular of twenty-four-hour news channels and Internet search engines is freeing us to take on tasks that we'd long assumed were limited to those with specialized training. Why, after all, should we pay commissions to real estate brokers or stock analysts when we can find online everything we need to sell our houses or manage our investments? And why should we blindly follow doctors when we can diagnose our own ailments?

One of the first effects of this hyper-democratization of data was to unmoor information from the context required to understand it. On the Internet, facts float about freely and are recombined more according to the preferences of intuition than the rules of cognition: Mercury is toxic, toxins can cause development disorders, mercury is in vaccines; ergo, vaccines cause autism. Combined with the self-reinforcing nature of online communities and a content-starved, cash-poor journalistic culture that gravitates toward neat narratives at the expense of messy truths, this disdain for actualities has led to a world with increasingly porous boundaries between facts and beliefs, a world in which individualized notions of reality, no matter how bizarre or irrational, are repeatedly validated.

Take the "birther" movement, which contends that Barack Obama was born in Kenya and therefore is not eligible to be president. In the summer of 2009, Orly Taitz, a Russian-born dentist/lawyer/real estate agent, almost single-handedly turned her one-woman media blitz into a national preoccupation. Taitz, who believes that the Federal Emergency Management Agency is building internment camps to house anti-Obama activists and that Venezuelan president Hugo ChÁvez controls the software that runs American voting machines, makes for undeniably good television: She looks like a young Carol Channing, sounds like an overexcited Zsa Zsa Gabor, and has the ability to make absurd accusations with a completely straight face. By midsummer, Taitz was appearing regularly on CNN, Fox News, and MSNBC, a decision the news channels justified with the risible pretext of needing to be fair to those on "both sides" of an issue about which there was nothing up for debate -- at least not in the real world. Before long, mainstream on-air personalities like Lou Dobbs were pimping the story as hard as Taitz or any of her allies were, to equally comical effect.

This type of cognitive relativism -- or "truthiness," as fictional talk show host Stephen Colbert termed it -- has become the defining intellectual trend of our time. Colbert coined truthiness as a way to define former president George W. Bush's disdain for "those who think with their head" as opposed to "those who know with their heart." Its pervasiveness was most tragically illustrated in Iraq: By inventing a set of facts to support the overthrow of Saddam Hussein, the Bush administration changed a discussion of whether Iraq had weapons of mass destruction to whether the theoretical presence of WMDs was sufficient justification for war. In the fall of 2004, after both WMDs and easy victory were revealed as mirages, a presidential aide made an astounding admission to The New York Times Magazine. The White House, he said, didn't waste time worrying about those "in what we call the reality-based community" who "believe that solutions emerge from your judicious study of discernible reality." That, the aide said, "is not the way the world really works anymore. . . . When we act, we create our own reality." Orly Taitz couldn't have put it any better herself.

My interest in the controversies surrounding childhood inoculations began in 2008. My wife and I were newly married, and though we didn't yet have children, we found ourselves initiates in a culture in which people obsessed over issues about which we'd previously been unaware, such as the political implications of disposable diapers and the merits of home births. Another common preoccupation, we discovered, was the fear that widespread fraud was being perpetrated by the medical establishment. These people were our peers: They gravitated toward fields like journalism or law or computer programming or public policy; they lived in college towns like Ann Arbor and Austin or sophisticated urban centers like Boston and Brooklyn; they drove Priuses and shopped at Whole Foods. They tended to be self-satisfied, found it difficult to conceive of a world in which their voices were not heard, and took pride in being intellectually curious, thoughtful, and rational.

And, we soon learned, a good number of them didn't trust the American Medical Association (AMA) or the American Academy of Pediatrics -- or at least didn't trust them enough to adhere to their recommended immunization schedules, which included vaccinations for diphtheria, hepatitis B, Hib, influenza, measles, mumps, pertussis, pneumococcal, poliovirus, rotavirus, rubella, and tetanus, all in the first fifteen months of a child's life. This caught us by surprise: The AAP wasn't high on the list of organizations we thought likely to be part of a widespread conspiracy directed against the nation's children.

That fall, we were at a dinner party when the subject of vaccines came up for what felt like the millionth time. I asked the parents at the table how they went about making decisions concerning their children's health. Did they talk to their pediatricians? Other parents? Were they reading books? Poking around online? One friend, a forty-one-year-old first-time father, said there was so much conflicting information out there he hadn't known what to do.1 In the end, he said, he and his wife decided to delay some shots, including the ones for the MMR vaccine, which he'd heard was particularly dangerous. "I don't know what to say," he told me. "It just feels like a lot for a developing immune system to deal with."

At the time, I had no idea what the evidence supported. Still, I cringed when my friend said he'd made his decision based on what he feltrather than by trying to assess the balance of the available evidence. Anecdotes and suppositions, no matter how right they feel, don't lead to universal truths; experiments that can be independently confirmed by impartial observers do. Intuition leads to the flat earth society and bloodletting; experiments lead to men on the moon and microsurgery.

The more I pushed my friend, the more defensive he grew. Surely, I said, there had to be something tangible, some experiment or some epidemiological survey, that informed his decision. There wasn't; I was even more taken aback when he said he likely would have done the same thing even if he'd been presented with conclusive evidence that the MMR vaccine was safe. "Let's say that there haven't been any studies that have uncovered a problem," he said. "That doesn't mean they won't find one someday." He was, of course, technically correct: It is always impossible to prove a negative. That's why gravity is still a "theory" -- and why you can't prove with absolute certainty that I won't wake up tomorrow with the ability to fly. (As Einstein said, "No amount of experimentation can ever prove me right; a single experiment can prove me wrong.") Finally, he offered up this rationalization: "If everyone agreed that vaccines are so safe, we wouldn't even be having this discussion." By that point, my wife was kicking me under the table. I let the subject drop.

But when I got home that night I couldn't stop thinking about that conversation. The issue didn't affect me directly: No one close to me had a personal connection with autism and I didn't know any vaccinologists or government health officials. What nagged at me, I realized, was the pervasiveness of a manner of thinking that ran counter to the principles of deductive reasoning that have been the foundation of rational society since the Enlightenment.

I began work on this book the next day. After reading hundreds of academic papers and thousands of pages of court transcripts, I couldn't help but agree with a federal judge who presided over an omnibus proceeding in which thousands of families with autistic children requested compensation for what they claimed were vaccine injuries: This was "not a close case."

Once I'd arrived at the conclusion that there was no evidence supporting a link between childhood inoculations and developmental disorders, I had to confront a set of issues that get to the heart of social dynamics and human cognition: Why, despite all the evidence to the contrary, do so many people remain adamant in their belief that vaccines are responsible for harming hundreds of thousands of otherwise healthy children? Why is the media so inclined to air their views? Why are so many others so readily convinced? Why, in other words, are we willing to believe things that are, according to all available evidence, false?

In an effort to answer those questions, I interviewed scientists and doctors, healers and mystics, government appointees and elected officials. I also spoke with dozens of parents who watched helplessly as their autistic children were enveloped by worlds outsiders could not penetrate. Some of these children were in obvious physical pain, some were sullen and unresponsive, some were violent and uncontrollable, and some moved from one extreme to another. The suffering of parents who feel unable to protect their children is almost impossible to describe -- and helplessness only begins to cover the range of emotions they endured. There was guilt: Despite everything they were told, it was impossible for some parents to fully rid themselves of a feeling that somehow their child's condition was their fault. There was resentment: Many were tired of having their lives taken over by a disease about which so little is known and so little can be done. There was bitterness: How could a society that propped up foreign governments and bailed out failing banks not pay for adequate services for disabled children? And there was anger: Surely someone or something was to blame for the ways in which their lives had been upended.

But more than anything else, parents spoke of their isolation. Those split seconds of synchronicity that freckle people's days -- the half-smile a new mom gives a pregnant woman on the street, the glance shared by two strangers reading the same book on the subway -- those are missing from a lot of these parents' lives. Those with children on the more extreme end of the autism spectrum tend to feel the most alone: There are no knowing winks when a child won't stop screaming, no "I've been there" grins when he defecates in public. No one thinks it's cute when a child scratches his mother until she bleeds and strangers don't chuckle when a ten-year-old wants to know why the woman who just got on the bus is so fat.

This sense of being cut off from the world helps to explain why tens of thousands of parents have gravitated to a close-knit community that stretches around the globe. The fact that the community's most vocal and active members believe that vaccines cause autism and that autism can be cured by "biomedical" treatments like gluten-free diets and hormone injections is of secondary importance -- what's paramount is the sense of fellowship and support its members receive. Every spring, between fifteen hundred and two thousand of these parents travel to Chicago's Westin O'Hare hotel for the annual conference of a grassroots organization called AutismOne, which claims to be the single largest producer of information about the disorder in the world. For those three or four days, the dynamic that shapes many of these parents' lives is turned on its head: Here, it's people whose lives haven't been affected by autism who feel out of place.

In order to protect this space, AutismOne discourages outsiders from attending. In incidents over the past several years, the organization has barred journalists identified as unsympathetic, kicked out parents who were perceived as being impertinent, and asked security to remove a public health official. This gatekeeping is severe but the worry behind it -- that only people with a vested interest in the organization's survival can be trusted to take a generous view of its beliefs -- is not misplaced. Even after I was granted permission to attend one of the group's conferences, I always had the feeling that my temporary visa did not come with the right to ask about the apparent contradictions highlighted by the weekend's proceedings.

The most obvious of these is the insistence by AutismOne's founders that they promote a "pro-science" and not an "anti-vaccine" agenda, a claim that is hard to reconcile with the group's mission statement: "The great majority of children suffering from autism regressed into autism after routine vaccination. . . . Autism is caused by too many vaccines given too soon."2 If anything, the conference's speakers have become more extreme as an ever-growing body of evidence disproves their claims: Included among the 150 presentations at the conference I attended was a four-hour-long "vaccine education" seminar, a lecture on "autism and vaccines in the US [legal system]," an environmental symposium on "the toxic assault on our children," and a presentation on "Down syndrome, vaccinations, and genetic susceptibility to injury." During her talk, Barbara Loe Fisher, the grande dame of the American anti-vaccine movement, explained how vaccines are a "de facto selection of the genetically vulnerable for sacrifice" and said that doctors who administer vaccines are the moral equivalent of "the doctors tried at Nuremberg." (That parallel, she said, had been pointed out to her by Andrew Wakefield, in whose honor the 2009 conference was held.) One night, there was the premiere of a documentary called Shots in the Dark, which examined "current large-scale vaccination policies" in light of the "onset of side effects such as autism or multiple sclerosis." This list could go on for pages.

If you assume, as I had, that human beings are fundamentally logical creatures, this obsessive preoccupation with a theory that has for all intents and purposes been disproved is hard to fathom. But when it comes to decisions around emotionally charged topics, logic often takes a back seat to what are called cognitive biases -- essentially a set of unconscious mechanisms that convince us that it is our feelings about a situation and not the facts that represent the truth. One of the better known of these biases is the theory of cognitive dissonance, which was developed by the social psychologist Leon Festinger in the 1950s. In his classic book When Prophecy Fails, Festinger used the example of millennial cults in the days after the prophesied moment of reckoning as an illustration of "disconfirmed" expectations producing counterintuitive results:

Suppose an individual believes something with his whole heart; suppose further that he has a commitment to this belief, that he has taken irrevocable actions because of it; finally, suppose that he is presented with evidence, unequivocal and undeniable evidence, that his belief is wrong; what will happen? The individual will frequently emerge, not only unshaken, but even more convinced of the truth of his beliefs than ever before. Indeed, he may show a new fervor about convincing and converting other people to his view.

In this light, another seeming paradox of the anti-vaccine movement -- its extreme paranoia about ulterior motives on the part of anyone promoting vaccination combined with an almost willful blindness to the conflicts of interest of the profiteers in their midst -- also makes more sense. In a speech delivered at eight in the morning of the first full day of the conference I attended, Lisa Ackerman, the head of a group called Talk About Curing Autism (TACA), ran through a long list of things parents "need" to do for their children, including testing for mineral deficiencies, installing water filtration systems, eating organic chickens, and throwing out all flame-retardant clothing, mattresses, and carpeting. "If you buy clothes and pajamas from Target and Wal-Mart, almost all of those have a flame retardant applied," she said. "If you're building or doing home improvement, that's like the biggest toxic exposure you can give a child. New carpets are one of the worst things you can do. Sorry if you just did it." Ackerman also talked about "supplementation [and] nutritional therapies," including "vitamin B12 shots in the buttocks" and antioxidant IVs, and described a range of other alternative treatments, many of which were available from the eighty-plus vendors who'd set up shop in one of the hotel's exhibition halls. (According to Ackerman, twenty-second treatments in one of the types of hyperbaric oxygen chamber for sale -- "They're not just for people like Michael Jackson; they're really cool!" -- had transformed her son from a "caveman" into a verbal child capable of having normal conversations.)

The following afternoon, the father-son team of Mark and David Geier stood on stage in the same lecture hall for the first of their two presentations on "New Insights into the Underlying Biochemistry of Autism." The most recent insight of the Geiers, who've been stalwarts of the anti-vaccine movement for decades, involved a treatment called the "Lupron protocol," which is based on a theory so odd it sounds like a joke: Autism, the Geiers were claiming, is the result of a pathological reaction between mercury and testosterone, and Lupron, an injectable drug used to chemically castrate sex offenders, is the cure. Before determining whether patients are candidates for their "protocol," the Geiers order up dozens of lab tests at a cost of more than $12,000. The treatment itself, which consists of daily injections and bimonthly deep-tissue shots, can run upward of $70,000 a year. It also is excruciatingly painful. (In an article in the Chicago Tribune, an acolyte of the Geiers' described giving a shot to one child: "His dad is a big guy like myself, [and] it took both of us to hold him down to give him the first injection. It reminded me of . . . a really wild dog or a cat.") At the time of the 2009 conference, the Geiers had already opened eight Lupron clinics in six different states. Mark Geier, who calls Lupron a "miracle drug," told a reporter that was just the beginning of their expansion aspirations: "We plan to open everywhere."

Outside the conference rooms of AutismOne and without a child suffering from the disorder, it can be hard to fathom how something as bizarre as Lupron ever gains momentum. But when you watch the transaction happening in real time it's not hard to understand its appeal. "If someone like Mark Geier comes up to you at a conference, and he's got twenty impressive PowerPoint slides, and he's got a Ph.D. and a long string of letters after his name, you're going to listen to him because you've been taught that someone like that is someone who knows what he's talking about," says Kevin Leitch, a British blogger and the parent of an autistic child. "And if this same parent reads in The Guardian or the London Times or The New York Times that a new study has been published in Science about a gene that might be associated with 15 percent of cases of autism, hooray. They look at that and think, 'Screw that. One of them is mildly interesting and the other gives me a load of hope.' "

The vast majority of parents, of course, don't bring such strong predilections to the topic of vaccines. What parents do want is to protect their children from infectious diseases while also being conscientious and informed about what is being injected into their bodies. A lot of parenting decisions come down to our gut reactions -- science can't tell us what's an appropriate curfew for a sixteen-year-old or whether it's better to indulge or resist a child who says he wants to quit violin lessons -- and when it comes to vaccines, most of the "commonsense" arguments appear to line up on one side of the equation: Vaccines contain viruses, viruses are dangerous, infants' immune systems aren't fully developed, drug companies are interested only in profit, and the government can't always be trusted. The problem, as psychologist and Nobel laureate Daniel Kahneman and his longtime research partner Amos Tversky demonstrated in a series of groundbreaking papers in the 1970s, is that in many situations regarding risk perception and data processing, "commonsense" arguments are precisely the ones that lead us astray.5 Because the risks associated with foregoing vaccines feel so hypothetical, and because the infinitesimally remote possibility that vaccines could hurt our children is so scary, and because there's nothing in our daily experience to indicate that a little fluid administered through a needle would protect us from a threat we can't even see, it's very hard for parents working by intuition alone to know what's best for their children in this situation.

This leaves us with two choices: We can either take it upon ourselves to do a systematic analysis of all the available information -- which becomes ever less feasible as the world grows more complex -- or we can trust experts and the media to be responsible about the information and advice they provide. When they're not, whether it's because they're naive or underresourced or lazy or because they've become true believers themselves, the consequences can be severe indeed. A recent Hib outbreak in Minnesota resulted in the deaths of several children -- including one whose parents said they do not "believe" in vaccination. In 2009, there were more than 13,000 cases of pertussis (more commonly known as whooping cough) in Australia, which is the highest number ever recorded. Among those infected was Dana McCaffery, whose parents do believe in vaccination, but who was too young to get the pertussis vaccine. She died when she was thirty-two days old. Six months later, Dana's mother got an e-mail from a woman in Dallas, Texas, named Helen Bailey. Bailey was looking for someone who might understand her grief: Her son, Stetson, died of pertussis when he was just eleven weeks old. If anything, the situation is getting even worse: In 2010, a yearlong pertussis outbreak in California was so severe that in September some foreign governments began warning their citizens of the dangers of traveling to the region.

Then there's measles, which is the most infectious microbe known to man and has killed more children than any other disease in history. A decade after the World Health Organization (WHO) declared the virus effectively eradicated everywhere in the Americas save for the Dominican Republic and Haiti, declining vaccination rates have led to an explosion of outbreaks around the world. In Great Britain, there's been more than a thousandfold increase in measles cases since 2000. In the United States, there have been outbreaks in many of the country's most populous states, including Illinois, New York, and Wisconsin. A recent outbreak in California began when a grade-schooler whose doctor supports "selective vaccination" was infected while on a family vacation in Europe. In an anonymously published article inTime magazine, that child's mother said she "felt safe in making the choice to vaccinate selectively" because she lives in "a relatively healthy first-world country" with a well-functioning health care system. "Looking at the diseases mumps, measles and rubella in a country like the US . . . it doesn't tend to be a problem," she said. "Children will do fine with these diseases in a developed country that has good nutrition. And because I live in a country where the norm is vaccine, I can delay my vaccines."

That statement could not be more false. Measles remains deadly regardless of whether you live in the United States or in Uganda. (Before the MMR vaccine was introduced, its annual death toll in the United States reached into the hundreds, and each year rubella infections resulted in more than twenty thousand infants who were born blind, deaf, or developmentally disabled.) This mother's conviction also perfectly encapsulates one of the most vexing paradoxes about vaccines: The more effective they are, the less necessary they seem.

On the fourth morning of Matthew Lacek's coma, a doctor told his parents that he appeared to have stabilized from the drop in his blood pressure the day before. There was a chance, the doctor said, that the antibiotics were winning the fight against the infection that had taken over Matthew's body -- but there was no way to know for sure until he woke up. For the rest of the day, Kelly and Dan sat by their son's bedside. Late that afternoon, he began to breathe on his own -- slowly at first, but then more regularly. It was getting dark outside when he blinked open his eyes. The first words out of his mouth were, "I want to go potty."

In April 2010, about a year after we first spoke, Kelly Lacek e-mailed me a picture of Matthew and his older brother, chins in hand, posing for the camera like a pair of tough guys. "We just celebrated [Matthew's] 7th birthday," she wrote. "It takes everything for me not to cry each day, let alone his birthday. We are so blessed to still have him. He had strep throat 4 times since January and each time his tonsils swell up, [he gets a] high fever and my husband Dan and I are reminded of that day." Kelly told me about her sons' Little League games and how much the whole family loves board games and sitting around campfires. "I hope that helps, Seth," she wrote. "Please let me know if you need anything else. . . . [It's important] to make sure families are making the right decisions, based on fact and not by fear or misinformation."

From The Panic Virus: A True Story of Medicine, Science, and Fear by Seth Mnookin. Copyright 2011 Seth Mnookin. Excerpted by permission of Simon & Schuster.