Vaccine
Safety > Issues of Interest > Autism
MMR
Vaccine and Autism
(Measles,
Mumps, and Rubella)
FACT
SHEET
Contents
of this page:
What You Should Know
-
MMR vaccine
protects children against dangerous, even
deadly, diseases.
-
Because
signs of autism may appear at around the
same time children receive the MMR vaccine,
some parents may worry that the vaccine
causes autism.
-
Carefully
performed scientific studies have found
no relationship between MMR vaccine and
autism.
-
The CDC
continues to recommend two doses of MMR
vaccine for all children.
Additional
Facts
-
MMR is a
combination vaccine that protects children
from measles, mumps, and rubella (also
known as German measles). The first dose
of the vaccine is usually given to children
12 to 15 months old. The second dose is
usually given between 4 and 6 years of
age.
-
In 1998,
a study of autistic children raised the
question of a connection between MMR vaccine
and autism.
-
The 1998
study has a number of limitations. For
example, the study was very small, involving
only 12 children. This is too few cases
to make any generalizations about the causes
of autism. In addition, the researchers
suggested that MMR vaccination caused bowel
problems in the children, which then led
to autism. However, in some of the children
studied, symptoms of autism appeared before
symptoms of bowel disease.
- In
2004, 10 of the 13 authors of the 1998 study
retracted the study's interpretation. The
authors stated that the data were not able
to establish a causal link between MMR vaccine
and autism.
- Other larger
studies have found no relationship between
MMR vaccine and autism. For example, researchers
in the UK studied the records of 498 children
with autism born between 1979 and 1998. They
found:
- the percentage
of children with autism who received
MMR vaccine was the same as the percentage
of unaffected children in the region
who received MMR vaccine
- there
was no difference in the age of diagnosis
of autism in vaccinated and unvaccinated
children
- the onset
of "regressive" symptoms of
autism did not occur within 2, 4, or
6 months of receiving the MMR vaccine.
- Groups of
experts, including the American Academy of
Pediatrics, agree that MMR vaccine is not
responsible for recent increases in the number
of children with autism. In 2004, a report
by the Institute of Medicine (IOM) concluded
that there is no association between autism
and MMR vaccine or vaccines that contain
thimerosal as a preservative.
- There is
no published scientific evidence showing
that there is any benefit to separating the
combination MMR vaccine into three individual
shots.
For more
information
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