So, is there a link between autism and vaccinations? In response to the recent media attention given to a possible link between autism and vaccinations, and other controversies concerning vaccines, the Immunization Action Coalition (IAC) has reprinted a special excerpt from Baby 411 that answers these questions and more. IAC is grateful to Dr. Brown for these clear answers and smart advices.
Dr. Brown received her medical degree from Baylor College of Medicine in Houston, Texas; she did her pediatric residency at Harvard Medical School/Boston Childrens Hospital.
In private practice since 1995, Dr. Brown is perhaps best known as the coauthor of Baby 411: Clear Answers & Smart Advice for Your Babys First Year (Windsor Peak Press).
By Ari Brown, MD, FAAP
There has been much talk about this theory, specifically that trace amounts of mercury used as a preservative in many vaccines prior to 2001 caused a spike in autism.
We discussed this issue in depth in Baby 411, but just to sum up: the scientific evidence does not support this theory. Research during the past ten years has taken a long hard look at vaccines and found conclusive evidence that vaccine exposure is NOT the turn-on switch for autism. And no, despite what you might read online from fringe groups or plaintiff lawyers, there is no conspiracy among pharmaceutical companies to inflict autism on unsuspecting children.
The U.S. Centers for Disease Control and Prevention (CDC) has long-term studies underway to examine vaccines and autism. The most recent results, published in the New England Journal of Medicine, showed that the mercury preservative previously present in vaccines had no significant effect on either intelligence or developmental delays in kids ages seven to 10.
The results of the CDCs study on mercury preservative and autism specifically will be published after this booklet goes to print. Stay tuned on our website for updates. A recent study in the journal Pediatrics found that premature babies born at 25 to 26 weeks gestation have a 25% chance of developing an autism spectrum disorder. BOTTOM LINE: Researchers dont know what causes autism, although the above factors provide clues. The goal is to find a way to PREVENT autism . . . but we arent there yet.
No. Mercury poisoning, also known as Mad Hatters Disease, is very different from autism. Symptoms of mercury poisoning include excessive sweating, tremors and kidney problems. Sufferers also talk and walk like they have had a stroke. How do we know this? The information known about mercury poisoning comes from unfortunate communities that have experienced it.
There is a large amount of data from the Faroe Islands, near Iceland. The people there would eat whale blubber contaminated with toxic levels of methyl mercury and polychlorinated biphenyls (PCBs). Children, especially those exposed as fetuses during their mothers pregnancy, seemed to have lower scores on memory, attention, and language tests than their unexposed peers. Heres the rub: despite all those problems, these children with mercury poisoning were NOT diagnosed with autism.
Another key point: mercury preservative was taken out of required vaccines SEVEN years ago. But autism rates are still going up. Did the mercury in vaccines cause autism? No. Here is the scientific evidence:
In 2001, the FDA required manufacturers to discontinue using mercury preservative for ALL routine childhood vaccines. Period. Many vaccines, like that for measles, mumps and rubella (MMR), have NEVER contained mercury preservatives. Nor is mercury used in the production process for MMR. However, there are four vaccines on the market that still use mercury preservative in the manufacturing processthe mercury is then REMOVED from the final vaccine.
Because the flu vaccine is reformulated each year for the upcoming season, manufacturers need to move as efficiently as possible to produce large quantities of vaccine. The best way to do this is to produce vaccine in multi-dose vials, which requires a preservative. There are, however, single-dose preparations that are FREE of mercury preservatives that can be given to young children and pregnant women, if available. Lets do a reality check here: a tuna sandwich has FIVE TIMES more mercury than one dose of flu vaccine.
As a doctor, I am much more concerned about mercury exposure in the environmentparticularly in food (like that tuna fish sandwich). So if you are worried about mercury exposure, consider this: theres mercury in breast milk. A baby gets 25 times more mercury by breastfeeding for six months than in a single dose of flu vaccine. Breast milk contains between 1.4 and 1.7 micrograms of methyl mercury per liter.
If you assume that a baby is breast-fed exclusively up until six months of age, that baby will consume about 360 micrograms of methyl mercury. Thats twice the amount of mercury that was ever contained in vaccines and 25 times the quantity of mercury contained in the influenza vaccine. A quick chemistry lesson: certain compounds have completely different properties even though they have similar sounding names.
For instance, there are TWO types of mercury: methyl mercury and ethyl mercury. The type of mercury that has raised health concerns is methyl mercury. Methyl mercury is a small molecule that can get into the brain and takes almost TWO MONTHS to break down. High concentrations of methyl mercury can be found in tuna, swordfish and shark from contaminated waters. Now, lets contrast that with ETHYL mercury, which is/was the type of mercury used in vaccine preservatives.
Ethyl mercury (thimerosal is an example) is rapidly eliminated from the body within a WEEK. Compared to methyl mercury, ethyl mercury is a much larger molecule that cannot enter the brain. Ideally, it would be nice to remove ALL mercury preservatives from flu vaccinesso we could put this controversy to rest. The problem: at this time, the only way to manufacture the huge quantity of flu vaccine needed each year requires using mercury preservatives. Hopefully, vaccine makers will figure out a way to eliminate mercury from all vaccines in the futureso any concerns can finally be put to rest.
The CDC publishes a recommended vaccine schedule for all children in the U.S.this schedule wasnt created from thin air . . . doctors, scientists and researchers work together to decide what is the best time to give shots. The goal: protect as many babies as soon as possible from deadly disease. Now, one of the popular myths about autism is that somehow kids are getting too many shots, too soon.
Despite the scientific evidence that shows vaccines do NOT cause autism, some parents think that if they space out their kids vaccines in an alternative schedule this is somehow safer. Adding to this notion are blogs, books, and web sites that promote alternative vaccine schedules, delaying critical shots months or years after a child can safely receive them. Heres a nasty little truth about alternative vaccination schedules: they are all fantasy.
There is absolutely no research that says delaying certain shots is safer. Doctors who promote these schedules are simply guessing when to give which shots. What we know for certain is that delaying your childs shots is playing Russian Roulette. The simple truth is you are leaving your child unprotected. Who knows what disease (preventable from a simple vaccine) will crop up next?
Deadly diseases like measles are only a plane flight away. Also: spreading out vaccinations creates new challenges. Live vaccines must be given at least four weeks apart to mount an active immune response. Take the MMR (measles, mumps, and rubella) vaccineyour child could get one combo shot and take care of all three deadly diseases at once. If you get three separate shots, however, it would take at least three months (because each is a live vaccine).
That leaves kids unprotected until the series is completed. When families demand a spaced out vaccination schedule, this is what I tell them as their doctor: At the end of the day, I just want your child vaccinated. If you want to give two shots today and two next week, thats okay. Just come back. And promise me you will do it in a timely manner (that means you return in weeks, not months or years, to finish vaccination). The goal: make sure the child is protected. One important point to remember: despite all the media attention to this subject, very few parents actually choose to delay or opt out of vaccinations.
Yes. As a doctor, I am greatly worried when parents decide to delay or not to vaccinate their child. Thats because vaccine-preventable diseases are real. I have watched a child die from a vaccine-preventable disease while I helplessly stood by. Ive cared for several babies gasping for breath with whooping cough. These diseases kill children. Respect them. Last year alone vaccines prevented 14 million infections and 33,000 deaths in the U.S. Our grandparents remember diseases like polio. And how folks lined up to get vaccinated. Yet, youve probably never even heard of anyone with polio today.
The great irony of vaccine success is that parents today are unfamiliar with the diseases they prevent. In the past 10 years, I have seen two forms of bacterial meningitis basically disappear, thanks to vaccines. Before the HIB (Haemophilus influenzae type b) vaccine was developed, there were about 20,000 U.S. children a year who suffered or died from this infection. Now there are less than 200 cases per year.
Before the pneumococcal conjugate vaccine, which protects against streptococcal meningitis, 17,000 American children per year had invasive infections with strep. And, about 200 kids died of this each year. Since vaccination, serious infections have been reduced by 90%. Thats pretty amazing. And no, you cant just let everyone else vaccinate their kidsand let them protect your un-vaccinated child.
Just look at the recent measles outbreak in 2008 in San Diego. It all started with a child, who was unvaccinated by parent choice. He returned from a trip to Switzerland with measles. He went on to infect TEN other unvaccinated childrenhis siblings, school friends, and three babies who were too young to be vaccinated who were exposed to that child in a doctors waiting room. Of the 11 cases, one baby was hospitalized. And this outbreak may be a trend.
During the period January through July of 2008, the highest year-to-date cases of measles were reported in the U.S. since 1996: 131 cases from 15 states and the District of Columbia. Over 90% were unvaccinated or had unknown vaccination status and two-thirds of these cases that were eligible for vaccination were not vaccinated because of philosophical or religious beliefs. There were also 16 babies who were too young to be vaccinated. Babies, who are the most vulnerable to serious infection, do rely on other vaccinated children in the community to protect them when they are not old enough to be immunized.
So, when people argue that kids get too many shots today, I ask them if theyd rather their child get meningitis. And what about vaccines in the pipeline? If weve already got too many shots, would you decide to skip a future vaccine to prevent HIV? Probably not. Thats because you know that vaccine might be the one that saves your childs life.
As you may have heard on the news, the government recently decided to compensate a child whose autism was allegedly triggered by a vaccine. Heres the background behind the headline: The Vaccine Injury Compensation Program has been holding special hearings called the Omnibus Autism Proceedings. This Vaccine Court is looking at allegations that 4900 children developed autism from vaccines.
The court is first looking at nine cases to form opinions about the evidence. One child, Hannah Poling, was awarded a monetary settlement. Hannah was born with a rare genetic disorder (mitochondrial disorder, which is a dysfunction in basic cell metabolism). This is the equivalent of being born with an undetected heart defecta ticking time bomb that could go off at any time.
For rare kids like Hannah, any stress could have caused her to develop autism. In fact, having a vaccine-preventable disease like the flu or chickenpox could have far worse health consequencesa disease like that could have killed her. Although she was not diagnosed prior to being vaccinated, experts recommend that even children with known mitochondrial disorders still be vaccinated. So even though the headlines screamed that (in this case) a vaccine caused autism, the facts of the case show this isnt true.
Hannahs underlying disease caused her deterioration and autism. The case was settled and determined that it did not represent a test case for the 4899 other children. Experts on mitochondrial disorders do NOT think this disease is the smoking gun that triggers autism. Thats because many folks have similar dysfunctional cells but never become autistic. And there is no simple test for mitochondrial disorders. Instead, you must do a difficult and painful muscle biopsy and a spinal tap. As a result, testing all kids for mitochondrial disorders is not necessary, ethical or practical. And even if your child is diagnosed with a mitochondrial disorder, the recommendation is still to vaccinate.
One small study of only eight patients in 1998 led a British research group to conclude that the combination MMR vaccine might cause autism.15 But in March 2004, after questions were raised about the study, ten of the 13 researchers of the study withdrew their claim of having found a possible connection between MMR and autism. They said, In this paper, NO CAUSAL LINK was established between MMR vaccine and autism as the data were insufficient now is the appropriate time that we should together formally retract the interpretation of the data suggesting a link.16
Numerous major studies (at least 17 so far) since 1998 also soundly refute this alleged link. The most prominent: the Institute of Medicines 2004 report clearly dispelled any link between MMR and autism. Perhaps the most compelling argument that the MMR vaccine does NOT cause autism is Japanin 1993, that country stopped using the combination MMR vaccine. Instead, Japanese children were given three separate shots for these diseases. Despite this change, autism rates in Japan continue to rise.17
The hysteria surrounding the MMR vaccine and the false 1998 report did have one serious consequence in England: a sharp rise in measles, mumps, and rubella after parents stopped giving their kids the vaccine. In 2004, only 80% of children in the U.K. were vaccinated against MMR. And look at the rise in cases of mumps: 1995: 1936 cases; 2003: 4265 cases; 2004: 15,503 cases. And remember, autism rates are rising in the U.K. as well. So, now theyve got both autism AND vaccine-preventable diseases. Its a lose-lose battleand the casualties are kids. Heres the bottom line: as a doctor who sees a large volume of kids, I have never seen a perfectly normally developing kid walk into my office, get his MMR vaccine . . . and come back next week with autism. It doesnt happen.
More vaccines are actually a GOOD thing! Every new vaccine protects more kids from getting sick . . . expensive hospital stays . . . and perhaps death or permanent injury. More kids are prevented from getting devastating diseases than ever before, thanks to vaccines.
What about getting several shots at once? Is that dangerous? Could you overload a childs immune system with these vaccine germs? Look at it this way: your child is exposed to thousands of germs on a daily basis (even if he is not in daycare). Exposing your child to five or eight different germs in the form of vaccines is a spit in the bucket. And young kids have a better immune response to vaccines than older children and adults.
Before a vaccine is approved for use by the government, its safety is extensively studied. These studies look at how kids respond to the vaccine. And so-called combo vaccines that incorporate several shots at once also consider the combined effect. Even if your child got 11 shots at the same time, he would need to use only about 0.1% of his immune system to respond to the vaccines.
The goal is to protect your child as quickly as possible from diseases that are very dangerous to young children. And even though the number of shots has gone up, the actual load on the immune system has gone down. Thats because todays vaccines are smarter and better engineered than the shots from a few decades ago. Case in point: whooping cough. Before 1991, the whooping cough vaccine had 3000 different germ particles (antigens).
Todays whooping cough shot has just three to five particlesjust as effective, but much better designed to be easy on your immune system. Before 1996, the polio vaccine was livethis carried a small risk of actually getting polio. Todays polio vaccine is dead (inactivated) . . . and carries NO chance of transmitting the disease. So, heres the irony: YOUR parents took much greater risk when getting vaccinated back in the 50s, 60s, and 70s. Today, even though we have many more vaccines, the risk is much lower. Our children are really getting smarter, safer vaccines today and better protection than we ever got as kids.
BOTTOM LINE: Vaccines do not weaken the immune system, they boost it.
Are there additives in the vaccines? Yes. And you should know about them. Vaccines contain the active ingredients that provide immunity. However, there are inactive ingredients that improve potency and prevent contamination. Here is a list of additives and why they are there.
If vaccines contain ingredients like aluminum or formaldehyde, wouldnt it be better if vaccine makers got rid of these additives? We agree that this sounds reasonablebut it doesnt mean that current vaccines are UNSAFE. Heres the key point: additives like aluminum in vaccines are in EXTREMELY SMALL amounts (often, just a trace). We are all exposed to significantly higher levels of environmental toxins in our everyday activities.
Lets look at aluminum. Babies ingest 50 micrograms of aluminum per liter of breast milk . . . and 500 micrograms of aluminum per liter of formula. By contrast, the amount of aluminum in a vaccine is much smaller. Do you wear antiperspirant? Thats got aluminum in it too. And aluminum is found in most food, soil, and water. So, to avoid aluminum exposure, youd have to stop wearing antiperspirantand basically leave the planet. And aluminum poisoning does not cause symptoms of autism, either.
Trace amounts (far less than what your baby eats everyday) of aluminum improve the bodys immune response to some vaccines. Thats why it is in there. Why is formaldehyde in vaccines? Well, small amounts sterilize the vaccine fluid so your child doesnt get something like the flesh-eating Strep bacteria when he gets his shots. If you use paper towels or mascara, or have carpeting in your home, youve been exposed to formaldehyde. Obviously, exposure to large amounts of formaldehyde is not a good thing for anyones health. But, again the amount in vaccines is extremely small. BOTTOM LINE: Vaccine additives are there for a reasonto make them safer and more effective.
Most pediatricians are ALSO parentsand docs dedicate their life to protecting kids. If I ever thought vaccines were harming kids, Id change what I do. I vaccinated my own kids and would do it again in a heartbeat. If you have any doubt about vaccinations, just ask your pediatrician if she vaccinated her kids.
It seems like just about everyones heard one of these heart-wrenching storieswhether it be a child with autism that you know personally, or a celebritys kid you hear about on TV. The parent reports that the child was developing just fine, until one day the lights just went out. Often, that phrase is accompanied by after he got his shots. And understandably, its enough to make any other parent freak out and think twice when its time to vaccinate his or her own child.
About 50% of parents with a child affected with autism spectrum disorder believe it was triggered by vaccination. However, the other 50% do not think vaccines had anything to do with it. Here is what I think, based on what I see in my own practice. Autistic kids were never typical to begin with. Not one patient of mine who has ASD was perfectly normal, got a vaccination, and returned the next week with autism.
In fact, all the parents in my practice whose children have ASD tell me that they either a) did not recognize the early differences in their childs development or that b) they always knew something was different about their child. The signs just became more apparent over time, the milestones stagnated, or the child seemed to lose skills. About one in five parents will report a loss of milestones. Thats what brings it to the parents attention.
An important fact: above, we noted that one in five parents report a loss in milestones. That means that a vast majority (80%) of kids diagnosed with autism spectrum disorder have no loss of milestones. They start out on a different developmental path and the symptoms become more apparent over time. One of my ASD patients moms, who is a medical professional, told me that she realized how clearly different her sons early development was after she watched her second child, without ASD, breeze through her developmental milestones. She had no frame of reference with her first child.
And since just about every parent has a camcorder these days, the developmental differences early in a childs life are easily chronicled on videotape for developmental specialists to review. They say the same thing I do. The child was never perfectly normal and these, sometimes, subtle differences are seen before a year of age. Heck, even the most vocal autism mom of all, Jenny McCarthy, who claimed on Oprah that her son was normal until receiving his combination measles-mumps-rubella vaccine, admits in her book that she missed the early signs of her childs ASD. Specifically, she said that it took her child until he was five months old to smile at her, when her friends babies all smiled by two months.
One of the leading autism experts in the country has told me that there are, indeed, an extremely small number of ASD children who have completely normal milestones and then regress, which is known as late onset autism. This type of autism likely represents a subset of children who have a distinct genetic abnormality that turns off spontaneously without any trigger at all. And this distinct group deserves genetic testing and more research. I know, I know, who are you going to believe? Dont I trust parents and their instincts? Absolutelyyou know your kids better than anyone else.
But having a child diagnosed with autism is a highly emotional experience. And the diagnosis is usually made around the same time a child is going through his vaccination series. Its true . . . but unrelated. Its true that vaccinations are happening, and its true that developmental differences become apparent. That doesnt mean they are related. Toddlers are also wearing diapers, drinking whole milk, and hanging out with parents who use cell phones.
Do diapers cause autism? How about cell phones or milk? Obviously, no. And let me be clear, parents arent the only ones who miss the early signs of autism. Pediatricians do, too. Full developmental assessments are often three to four hours in a specialty referral center. We rely heavily on parents to point out their concerns. Parents and doctors can both miss early signs of autism spectrum disorders in the first year of life. This is one of the key reasons why the American Academy of Pediatrics created an Autism Toolkit in 2007 for its doctors to learn the signs, screen specifically for autism at every well child visit, and provide resources and educational materials for affected children.
BOTTOM LINE: Stoking parents fears about vaccines with false rumors about link between Autism and vaccinations safety is irresponsible and creates a lose-lose situation for societyand the casualties are children. Vaccines work. And they are safe. Rather than demonize vaccines, we (doctors, parents, researchers, the government) should put our time, effort, and money into researching the CAUSES of autism and the best possible treatments.
Learn more about Characteristics For Autism Spectrum Disorders, an Early Symptoms of Autism, a rationale behind Autism treatments...