MMR vaccine (still) doesn't cause autism, new study finds

Nope.

We’re still spending vast amounts of time and money trying to counter the ill effects of a discredited, retracted paper from 1998 that claimed to find a link between the MMR (measles, mumps, and rubella) vaccine and autism. Even after the The Lancet retracted the study, and even after the British Medical Council revoked the medical license of its lead author, Andrew Wakefield, many people continue to withhold vaccines from their children because of a fear that somehow, despite all the evidence to the contrary, vaccines might cause autism. Vaccines, I hasten to add, have saved millions of lives and are probably the greatest medical advance of the past two centuries.

Now another study has appeared to add more weight to the evidence about the safely of the MMR vaccine. The new study by Anjali Jain and colleagues, just published in the Journal of the American Medical Association, looked at a huge number of children–95,727–for evidence of any link between autism and the MMR vaccine.

The results were not surprising, to those who have been following the science. To quote the conclusions directly: 

“Receipt of the MMR vaccine was not associated with increased risk of ASD [autism spectrum disorder], regardless of whether older siblings had ASD. These findings indicate no harmful association between MMR vaccine receipt and ASD even among children already at higher risk for ASD.”

That should settle it, right? But then, dozens of previous studies should have already settled this question. Unfortunately, due to the ongoing activism of anti-vaccine groups such as Age of Autism, (who already attacked this new study) and to conspiracy theorists such as Robert F. Kennedy Jr. (whom I wrote about last summer, and who was campaigning against vaccines in Vermont just last week), misguided claims that vaccines cause autism or neurological problems persist.

Here are the numbers from the new study. The authors compared vaccinated children to unvaccinated children, using a huge database of medical claims that included at least 5 years of followup. (This was an "observational" study, by necessity–it would be unethical to withhold vaccines from children on purpose.) The relative risk for autism in children who had 2 doses of the MMR vaccine (the recommended amount) compared to unvaccinated children was 0.74. In other words, a child was somewhat less likely to be diagnosed with autism if he or she were vaccinated. 

Even more surprising was the relative risk among children who had an older sibling with autism: in this smaller group, children with 2 doses of MMR were just 44% as likely to be diagnosed with autism as unvaccinated children. This statistically significant finding indicates, unexpectedly, that vaccines might actually protect children from autism.

The authors were quick to note that there are other good reasons for this apparent protective effect of vaccines: in particular, if parents of autistic children withheld vaccines from their younger children, this could explain the effect. Why? Because we know that autism has a genetic component, and that if one child has autism, his younger sibling is more likely (because they share many genes) to have autism as well. Jain and colleagues explained that if these parents withheld vaccines–because of fears spread by the anti-vaccine movement–then their children could contribute to the apparently lower rate of autism in children who were vaccinated. The authors couldn’t rule out a protective effect of vaccines, but scientifically it seems unlikely, and they wisely offered an alternative explanation.

So: once again we have a large, carefully conducted study showing that the MMR vaccine does not cause autism, and even finding evidence that vaccinated children have lower rates of autism. Let's hope this study helps to end the anti-vax movement, so that we can soon stop spending time and money trying to refute their long-discredited hypotheses and instead focus on trying to understand the true cause.

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.

Brief note: a new vaccine mythbuster site appears

Vaccines are probably the single greatest advance in public health ever invented. Despite their enormous benefits, and the overwhelming evidence in their favor (we've wiped out smallpox and nearly wiped out polio), anti-vaccine activists continue to spread rumors and wildly inaccurate, but scary tales about the potential harms of vaccines.

Today a new website was published, a collection of 100 other sites that provide good information on the benefits of vaccines, and that bust many of the most damaging anti-vaccine myths.  This site is on the list, but you'll find many other excellent sources of good science about vaccines.  We need every bit of help we can get to counter the mis-information about vaccines promoted by groups such as Generation Rescue and Age of Autism.

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.

Should a doctor fire an anti-vax patient?

The anti-vaccination movement continues to grow, despite the retraction and thorough discrediting of the 1998 scientific study that spurred much of its growth.  The stubborn persistence of anti-vaxxers shows how difficult it is to dispel misinformation once that information is out there, even after dozens of new studies and millions of dollars in research that demonstrate that vaccines are safe.

One of the most dangerous trends is the growing number of parents who refuse to vaccinate their kids, or who choose "alternative" vaccine schedules, such as the one promoted aggressively by Robert Sears (who goes by "Dr. Bob").  Sears appears to have simply invented this alternative schedule without bothering to conduct any scientific studies, in part to promote sales of his 2007 book, The Vaccine Book: Making the Right Decision for Your Child.  Vaccine expert Dr. Paul Offit explained, in a 2009 article in the journal Pediatrics, why Dr. Sears' schedule was a very poor choice for children and for the public health.  After thoroughly dismantling Sears' anti-science positions, Offit concludes, "Sears has a poor grasp of the scientific method."  That's an understatement.

Other doctors, perhaps jealous of all the attention that Sears has gained through his anti-vaccine writings and television appearances, have created their own alternative vaccine schedules.  One of them, Donald Miller, even goes so far as to say that vaccines cause childhood cancer, despite the complete lack of evidence for this wild claim.  Somehow Sears, Miller, and others like them have managed to convince many parents that their children don't need vaccines.

In response to parents who don't want to vaccinate, many of whom show up with Dr. Bob's schedule in hand, pediatricians have struggled to find an effective response.  Parents can be utterly convinced by the misinformation they find on the Internet, which is all too easy to find.  (For example, Googling "vaccine" brings up the National Vaccine Information Center, a hotbed of anti-vaccine propaganda and pseudoscience, on the first page of hits.)  By the time parents arrive with their babies for the first vaccine, convincing them to change their minds can be nearly impossible.

Perhaps in frustration, doctors have started to "fire" their patients if they refuse to vaccinate.  As reported by Shirley Wang in The Wall St. Journal last week, 20-30% of doctors in two different surveys, in Connecticut and the Midwest, reported having to kick patients out of their practices because of vaccine refusal.  These numbers have roughly doubled over the past ten years, according to the American Academy of Pediatrics.

Is firing a patient the right thing to do? It's a difficult question.  On the one hand, doctors should do everything they can to make sure kids are vaccinated.   If a doctor kicks a parent out, that parent may find another doctor who doesn't insist on vaccinating children, which ultimately harms the children.  Doctors have to spend more time educating parents about the tremendous benefit of vaccines, about the very strong evidence (based on tens of millions of doses) for vaccine safety, and about the frightening consequences of infection with meningitis, hepatitis, measles, polio, and other vaccine-preventable diseases.

On the other hand, unvaccinated children bring diseases into the pediatrician's office, where they can spread them to other children.  Some of these other children are too young to be vaccinated, and childhood infections can be extremely dangerous, even fatal, in the very young.  From this perspective, "firing" a patient might be the only responsible action, after first trying to convince the parents to vaccinate.  I know that I wouldn't want to bring my child to a doctor's office where unvaccinated children were in the same room.

I understand how nervous a parent can be about vaccinations.  I will never forget the day my older daughter got her first vaccine: the needle looked huge compared to her tiny leg, and she screamed when the doctor gave her the shot.  But she was fine a few minutes later, and she'll be protected against a dangerous infection for her entire life.  Vaccines have been so successful at eliminating childhood infections that parents no longer see these infections as a threat.  Ironically, the very success of vaccines has allowed the anti-vaccine movement to sway so many people.

Doctors may have to keep firing the parents of their young patients, but I hope they'll first make every effort to educate them.  They need to explain that vaccines do not cause autism, nor do the ingredients in vaccines, and that scientific studies involving hundreds of thousands of patients support these conclusions.  They should also explain that many of the anti-vaccination claims on the Internet started when Andrew Wakefield published one small study of 12 patients, now retracted, claiming a link between the MMR vaccine and autism.  Investigations later revealed that he was paid by lawyers to recruit patients for a lawsuit against vaccine makers, that he didn't reveal these payments to his co-authors or the patients, and that he manipulated the data.  Since then, the anti-vaccine movement has exploded and we've experienced multiple outbreaks of measles, mumps, and other illnesses linked directly to unvaccinated children.

Doctors interviewed by the Wall St. Journal reported that they had convinced at least some parents to follow the recommended vaccine schedule.  Perhaps that's the best we can hope for.  If we're going to avoid a return to the era when children routinely died from infections, we must keep trying.

Supreme Court saves the vaccine system

Unbeknownst to most people, the Supreme Court heard a case last week that, had they ruled differently, might have destroyed the vaccine system in the United States. On February 22, the court ruled 6-2 to keep the special Vaccine Court system intact. In particular, they ruled against Russell and Robalee Bruesewitz, who were suing for damages on behalf of their daughter Hannah. But even though the system is saved for now, the two judges who voted in the minority demonstrated a frightening disregard for possible consequences, and encouraged those who would like to take us all back to an era when millions of children died each year from diseases like measles, polio, and whooping cough.

Hannah Bruesewitz's case is heartbreaking: she suffered a seizure in April 1992, within a day of receiving the vaccine for diphtheria, pertussis, and tetanus (DPT), and she had many more seizures in the following months. She was eventually diagnosed with with “residual seizure disorder” and “developmental delay" which she still has today. Her parents blamed the vaccine, and in 1995 they sued in Vaccine Court. They lost, although the Special Master of that court awarded them $126,800 for lawyer's fees and other costs. The Bruesewitzes rejected the award and sued in a state court in Pennsylvania.

The case last week wasn't about whether Hannah's disability was caused by the DTP vaccine. It was only about whether her parents could sue in state court after losing their case in vaccine court. The Supreme Court said no. Had they allowed the case, state courts across the country would have been flooded with thousands of vaccine lawsuits, and it is entirely likely that vaccine makers would simply stop selling vaccines in the United States. The ensuing loss of vaccines would be a public health disaster of enormous magnitude, leading to tens of thousands of deaths from diseases that we now have largely defeated in this county.

This sounds awfully dire. Why do I claim it could happen? Because it almost did, some 25 years ago.

Back in the 1980s, largely due to one incredibly irresponsible, inaccurate television documentary called DPT: Vaccine Roulette "started a firestorm" of panic, as Paul Offit explains in his latest book (1). It also caused an avalanche of lawsuits, and juries were soon making multi-million dollar awards. As Dr. Offit documents, jury awards in vaccine cases increased from $25 million in 1981 to $3.2 billion in 1985. Two of the three companies making the DPT vaccine stopped distributing it, leaving only one company, Lederle (now owned by Wyeth) supplying it.

It wasn't just DPT. Companies making measles and polio vaccines also dropped out of the U.S. market, leaving just one company for each. We were very close to a situation where we simply wouldn't have childhood vaccines in this country.

Then, remarkably, the federal government passed the National Childhood Vaccine Injury Act of 1986. This set up a special fund to compensate anyone damaged by vaccines, covered by a tax on all vaccines. It also created a special Vaccine Court to hear cases, and required that vaccine cases go through this court. The standard of evidence for the court was lower than regular courts: for some conditions, the parents merely have to show that their child suffered the condition soon after getting a vaccine, regardless of whether the vaccine was the cause.

The law also took juries and state courts out of the equation. Vaccine makers were protected, and the childhood vaccination system was saved. The Vaccine Court functions remarkably well, using Special Masters who become far more educated about vaccines and possible side effects than any regular judges can be. There is a very small but real risk of harm from vaccines, and the Vaccine Court has made thousands of awards to compensate victims. Meanwhile, millions of severe illnesses and countless thousands of deaths have been prevented by vaccines.

So I was very dismayed that two justices, Sandra Sotomayor and Ruth Bader Ginsburg, voted against the majority. I usually agree with these two, but their reasoning in this case was wildly off. Sotomayor's dissent shows her to be misinformed, confused, or just plain naive:

"Trial courts, moreover, have considerable experience in efficiently handling and disposing of meritless products liability claims, and decades of tort litigation (including for design defect) in the prescription-drug context have not led to shortages in prescription drugs. Despite the doomsday predictions of respondent and the various amici cited by the concurrence ... the possibility of a torrent of meritless lawsuits bankrupting manufacturers and causing vaccine shortages seems remote at best."

Apparently Sotomayor is unaware of the actual "torrent of meritless lawsuits" from the 1980s that forced Congress to create the Vaccine Court in the first place, although I cannot understand how she could fail to know this history. I am also disappointed by her naive faith in trial courts to quickly dispose of "meritless product liability claims." Perhaps in an ideal world, yes. But a smart lawyer, a sympathetic victim, and a complex medical case can easily confuse both judge and jury, leading to enormous jury awards regardless of what the scientific evidence shows.

Apparently Sotomayor can't bear to limit the ability of plaintiffs to sue wherever they choose. The Vaccine Court, although imperfect, is a much better model for handling complex medical claims than the roulette of a jury trial. We should all breathe a sigh of relief that the Supreme Court kept this system intact.

Of course, the anti-vaccination movement has been quick to attack the decision. Age of Autism, one of the biggest anti-vax sites, posted an article titled "Supreme Court Ruling Abandons Vaccine-Injured Children, Threatens Vaccine Safety" in which they call the decision "a crushing blow to the rights of every U.S. citizen." A coalition of anti-vax organizations including Generation Rescue issued a press release calling the decision "misguided" and making a number of incorrect claims about vaccine safety. But scientists and doctors, notably the American Academy of Pediatrics, applauded the decision.

Reference

1. Paul A. Offit, M.D. Deadly Choices: How the Anti-Vaccine Movement Threatens Us All. Basic Books (2011). See especially pages 2-12.

"Recontrolling pertussis": a phrase we shouldn't have to hear

The word is going out that a lot of people need to get a pertussis booster shot Pertussis, more commonly known as whooping cough, is a bacterial infection that is very dangerous and sometimes fatal in young infants, whose immune systems are too immature to protect them. The only way to protect the very young is to make sure those around them -- parents, siblings, other relatives, and day care providers -- are vaccinated. Many adults were vaccinated as children, but the vaccine's protection wanes after about ten years, so they still need a booster shot if they are caring for children.

What's new here? First, there's a new report from an expert advisory panel to the Centers for Disease Control. The CDC panel is urging doctors to vaccinate everyone who might be in contact with young children, even if they can't remember when or if they had the pertussis vaccine. A report in the Journal of the American Medical Association this past week quotes pertussis expert Michael Brady, M.D., who chairs the American Academy of Pediatrics committee on infectious diseases, who says the new recommendations are needed as part of our efforts at "recontrolling pertussis."

What does Dr. Brady mean when he says "recontrolling"? Well, whooping cough is not under control right now. In California, a serious epidemic continues. (See my previous post about it here.) The CDC reports over 7,800 cases of pertussis throughout California, including the deaths of 10 infants. These infants were too young to be vaccinated, and their deaths are a tragedy that could have been prevented. The last time we saw this many cases of whooping cough in California was 63 years ago, in 1947.

Meanwhile, Michigan continues to have its own pertussis outbreak, with 1,092 cases this year, and 902 cases last year. And the pertussis epidemic has spread to Ohio, where two counties collectively report 910 cases this year, the largest number in 25 years.

In infants and very young children, pertussis causes violent, spasmodic coughing that repeats over and over. The cough is so strong that babies cannot breath properly, and after multiple coughs they will breathe in sharply with a classic "whooping" sound, which gives the disease its name. Pertussis is far more dangerous in infants than in adults: from 2000-2004, 92% of the pertussis deaths in the U.S. were in children less than one year old.

Whooping cough used to be under control. The number of nationwide cases was dropping for years, and although the disease didn't disappear, we were getting to the point where most people didn't know anyone who'd had it. The question is, why did we lose control? Is a new strain of pertussis to blame? Or is it our own behavior?

Unfortunately, the answer seems to be that these outbreaks are spreading as a result of falling vaccine rates, for which we can thank the anti-vaccine movement, which has been very effective at getting their message out through mainsteam media, including the Larry King show, Oprah, and The Huffington Post. One of the main groups in this movement is the mis-named National Vaccine Information Center, which really should be called the Vaccine Misinformation Center. Their pertussis web page contains a section titled "Can pertussis vaccine cause brain damage and death?" The mere act of asking this question is part of their anti-vaccine strategy. And rather than answering "no," the website goes on for several paragraphs, selectively quoting from studies that looked at vaccine risks - which are very small, but not zero - while ignoring the much greater risks of the disease itself. NVIC's website concludes by claiming (without citation) that

"Most pediatric neurologists acknowledge that vaccination, including use of vaccines for smallpox, rabies, influenza, mumps, measles, tetanus, polio and pertussis, can and does occasionally cause neurological complications that can lead to permanent brain dysfunction."

Scare tactics indeed. Not only is NVIC trying to scare parents away from the pertussis vaccine, but they take the opportunity to warn against many other vaccines. NVIC claims on its website that it "does not promote the use of vaccines and does not advise against the use of vaccines," but that, to put it bluntly, is a lie. Their primary mission is anti-vaccine advocacy, as illustrated by their current advertising campaign that claims we are "over-vaccinating" children and injecting them with harmful toxins.

So we can thank NVIC and other anti-vaccine groups, such as Generation Rescue (which claims, among many other mistaken notions, that the pertussis vaccine causes autism), for the re-emergence of whooping cough.

In contrast, here's what the CDC says about the pertussis vaccine:

"Results from clinical trials showed that these vaccines are very safe for infants and children....The most common adverse events reported have been tenderness and redness where the shot was given, headache, diarrhea, and fussiness."

Unlike NVIC, the CDC gives details and citations to the scientific literature. The CDC also maintains a separate page listing all possible side effects from a long list of vaccines.

The current vaccine against whooping cough is called DTaP or TDaP (short for " tetanus toxoid, reduced diphtheria toxoid and acellular pertussis", and the evidence shows that it is very safe. The vaccine does not contain any whole cell, not even killed bacteria, meaning that it is impossible for the vaccine to cause even a mild case of any of the diseases that it protects against.

The CDC advisory on the pertussis vaccine is not part of a conspiracy to "over-vaccinate" the public, or to pad the profits of Big Pharma. (By the way, to pre-empt some of the commenters: I am not paid a single penny by any pharmaceutical company, nor am I paid by Forbes.) The advisory is a necessary step to "recontrol" whooping cough, a disease that we should not have let back into our communities. I fear that if we keep listening to the anti-vaccine activists, pertussis will be just the first in a series of diseases that will return to plague us, causing needless suffering and anguish.