Do vaccines cause autism?
“There is no link between any vaccine and autism,” says pediatrician Ari Brown, spokesperson for the American Academy of Pediatrics.
As the autism rate increased over the last two decades, theories surfaced blaming vaccines for the rise. Some believed thimerosol, a mercury-derived preservative found in several inoculations, was the culprit. Others blamed an inflammatory response to the measles mumps rubella (MMR) shot. But numerous scientific studies, including a definitive 2004 Institute of Medicine report, have debunked those theories.
How did the autism and vaccinations scare begin?
In 1998, Dr. Andrew Wakefield published a study in the respected medical journal, The Lancet. In it, Dr. Wakefield theorized that the MMR shot caused leaky gut, sending toxins into the bloodstream and the brain, triggering the changes that resulted in autistic behaviors.
A year later, a federal study showed high levels of ethylmercury (a byproduct of thimerosol) in childhood vaccines. Concern then stirred that thimerosol, along with the MMR shot, might be a culprit in the surge of autism diagnoses that started in the 1980s.
Both theories have been debunked. Dr. Wakefield’s research, which was based on 12 children with autism, has been discredited numerous times by studies involving hundreds of thousands of people, none of which were able to replicate his results or prove his theory. Critics say Dr. Wakefield’s theory was not only wrong, it threatened public health. In England, where MMR vaccination rates fell after Dr. Wakefield’s autism study was published, 1,000 children contracted measles, a severe disease that often results in hospitalization and sometimes, death.
Thimerosol was removed from most childhood vaccines (it’s still in some versions of the flu shot) in 1999. There was no proof that ethylmercury was toxic at the levels seen in vaccines, but because the same level of methylmercury was known to be toxic, the preservative was ordered removed as a safety precaution. In the years since thimerosol was removed from vaccines, the rate of autism has not fallen. To the contrary, it’s risen, showing there was no link between the two.
If vaccines don’t cause autism, what does?
The truth is that no one knows for sure. Genes seem to play a part. A family with one autistic child has a greater than average chance of having a second child with autism. Certain genetic conditions, such as Fragile X and Down’s syndromes, also increase the risk. Some studies have indicated that autism begins in the womb, when something goes awry with brain development. Babies of fathers over age 40 have a greater risk, as do babies born before 25 weeks gestation and under a pound at birth.
How does research explain the parents who swear their babies were fine before vaccination?
Odds are that those babies were showing signs before the MMR shot, which usually occurs around the first birthday. “I’ve been practicing pediatrics for 15 years and I have never had a child, perfectly normal, walk into my office, get their MMR shot, and come back the next week with autism,” Dr. Brown says. “It just doesn’t happen that way. The signs can be very subtle, and often the parent does not pick up on them.”
Is it coincidence that autism rates rose just as the number of vaccines given to children increased?
It is true that the number of autism diagnoses has increased 14-fold since the
1980s, to now affecting one in 150 children. And the number of vaccines given to children has also risen since the 1980s. But autism experts say this is a function of better diagnostic tools, not evidence of increased incidence. Autism is a collection of disorders, including Asperger’s Syndrome and Pervasive Developmental Disorder. Some research estimates that Asperger’s, which wasn’t included in the autism spectrum until 1994, now accounts for 50 percent of identified cases.
I worry about my child getting so many vaccines all at once, so I’m considering delaying certain shots. Is this safe?
The CDC and AAP recommend against straying from the recommended vaccination schedule. “There is no proof that these staggered schedules are safer,” says Dr. Brown. “In fact, they put our most vulnerable patients, our babies, at risk because you’re leaving them unprotected for a longer period of time.”
Prominent pediatrician Bob Sears, author of The Vaccine Book, has developed a delayed vaccination schedule which he says focuses on the most dangerous diseases and gives parents the control they crave over their child’s inoculations.
The AAP does not support delayed vaccination. Dr. Sears admits that, “My schedule doesn’t have any research behind it,” which is part of Dr. Brown’s criticism. “No one has ever studied a big group of kids using my schedule to determine if it’s safe or if it has any benefits,” he says, adding that he would welcome such a study. But until then, he says his schedule gives fearful parents, who might otherwise decide not to vaccinate at all, an option they feel more comfortable with. “In my mind that’s going to increase the vaccination rate,” he says.
What risks do I take by delaying or avoiding vaccination altogether?
The CDC vaccine schedule was designed to ensure maximum protection for children at the ages when they need it most. For example, Haemophilus influenza (Hib) once killed 600 children per year in the U.S. Since its introduction in 1987, fatality rates have fallen 98 percent. Of greatest concern is that when children are not vaccinated, we lose “herd immunity” and diseases can start to resurface. This can be of greatest risk to infants who do not yet have full immunity to diseases that can be especially devastating to their young bodies.
What if I already have a child with autism? If I vaccinate my other kids, am I putting them at risk?
The unfortunate truth is that children with a sibling or parent with autism are at greater risk for the disorder, regardless of vaccination status. So the American Academy of Pediatrics recommends vaccination of all children, despite family autism status.
How can I know for sure that vaccines are safe for my kids?
We know vaccines are safe because nearly all children receive them without any serious adverse affects. “The vaccination schedule that’s recommended by the AAP and Centers for Disease Control is put together by numerous experts who have looked at the studies and it’s based on science,” Dr. Brown says. “The goal is to protect babies as soon as it is safe and effective to do so. It works, it’s safe and there’s no proven link between (vaccines and autism).”
What should I do if I still have concerns?
Talk to your children’s pediatrician. He or she will be able to explain which vaccinations are recommended at which ages, how many are given at once and why this is safe. The doctor will also let you know what reactions are normal, such as soreness at injection site, and which are cause for concern.
“If you have vaccine concerns, the one question you should ask your pediatrician is, did she vaccinate her kid?” Dr. Brown says. “Because why the heck would we ever do anything different for our kids? I have complete faith in the vaccinations.”