Is there a connection between vaccines and autism?
Autism is a term used to describe a group of conditions that involve brain development known as autism spectrum disorders (ASDs) or pervasive developmental disorders (PDDs). Currently, it is estimated that about 1 in 150 children has an ASD.
The cause(s) of these disorders is unknown; however, over the years many theories have appeared in the media suggesting that they might stem from a host of causes, including food allergies, excessive amounts of yeast in the digestive tract, and exposure to mercury or other environmental toxins. None of these theories have been scientifically proven.
The results of two studies done by Dr. Andrew Wakefield and colleagues (which were published in 1998 and 2002) led Dr. Wakefield to propose that the altered measles virus in the MMR (measles-mumps-rubella) vaccine, or infection with naturally occurring measles virus itself, might cause autism. Others have speculated that the very small amounts of mercury that were used as a preservative in some vaccines might also be a cause (the MMR vaccine has never contained mercury, and mercury has been completely removed from nearly all vaccines available today).
Many scientists have found serious problems with Dr. Wakefield's research and question the validity of his findings. And recently, the editors of the medical journal Lancet, which published Dr. Wakefield's study, said that the flaws were so significant that they've withdrawn the paper from their publication. Also, recently published results from several large, well-controlled, scientifically sound studies indicate that there is no link between vaccines — or any of their ingredients — and autism.
It's clear that the risks of serious reactions to the MMR and other recommended vaccines are small compared with the health risks associated with the often-serious diseases they prevent. But if you have concerns about any vaccine for your child, talk to your doctor. Ask about the benefits and risks of each vaccine and why they're so important for safeguarding your child's health.
Reviewed by: Steven Dowshen, MD
Date reviewed: March 2010
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