There has been ongoing controversy surrounding certain vaccines and
their relationship to autism. Some parents have been concerned that vaccines,
specifically the measles-mumps-rubella (MMR) vaccine and preservatives used in
other childhood vaccines, play a role in children developing autism. Some
stopped vaccinating their children altogether because of this concern.
Thimerosal in vaccines
Parents questioned whether mercury-containing thimerosal (used as a
preservative in vaccines) might cause autism. Today, with the exception of some
influenza vaccines, none of the vaccines used in the United States to protect
preschool-aged children against 12 infectious diseases contain thimerosal as a
preservative. (Influenza vaccine is currently available both with thimerosal as
a preservative and preservative-free.) More importantly, studies have not found
a link between thimerosal-containing vaccines and autism.1
Vaccine combinations
Parents also questioned whether the MMR vaccine—which combines 3
vaccines into 1 injection—causes autism since symptoms of
the disorder often become apparent about the time children start getting
immunized.
In response to this concern, researchers in Europe, Canada, and the
United States looked closely at this issue. Studies have looked at the timing
of the vaccine and the vaccine itself and have found no link between the
vaccines and autism.
Because the exact cause of this sometimes devastating condition is
not known, some parents will continue to have concerns despite the evidence.
In these cases, parents should be aware of the risks of serious disease in
children who are not vaccinated. In some areas, outbreaks of these dangerous
diseases have occurred in people who have not been immunized.