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 Concerns about a potential link between the MMR vaccine and autism
have persisted for two decades, since a controversial and ultimately
retracted 1998 paper claimed there was a direct connection. Even
though subsequent studies haven't tied inoculation to autism, fear
about the risk has weighed on parents so much in several communities
across Europe and the U.S. that vaccination rates have been too low
to prevent a spate of measles outbreaks.
In the current study, researchers examined data on 657,461 children.
During this time, 6,517 kids were diagnosed with autism.
Kids who got the MMR vaccine were seven percent less likely to
develop autism than children who didn't get vaccinated, researchers
report in the Annals of Internal Medicine.
"Parents should not skip the vaccine out of fear for autism," said
lead study author Dr. Anders Hviid of the Statens Serum Institut in
Copenhagen, Denmark.
"The dangers of not vaccinating includes a resurgence in measles
which we are seeing signs of today in the form of outbreaks," Hviid
said by email.
Measles is a highly contagious virus that can be fatal. It starts
with a fever that can last a couple of days, followed by a cough,
runny nose and pink eye. A rash develops on the face and neck and
then spreads to the rest of the body. In severe cases, pneumonia and
encephalitis, an inflammation of the brain, can develop.
People with measles can spread the virus for several days before and
after the rash appears.
The virus can live for up to two hours on surfaces where an infected
person coughs or sneezes. People can become infected by breathing in
droplets or touching a contaminated surface and then touching their
eyes, nose or mouth.
Just a five percent reduction in vaccination coverage can triple
measles cases in the community, researchers note.
Researchers studied the connection between the MMR vaccine and
autism in a nationwide cohort of all children born in Denmark to
Danish-born mothers from 1999 to 2010. They followed kids from age
one through the end of August 2013.
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Overall, 95 percent of the kids in the study got the vaccine.
Children with autistic siblings were more than seven times more
likely to be diagnosed with autism than kids without this family
history, the study found.
Boys were four times more likely to be diagnosed with autism than
girls, the study found.
And, children who had no childhood vaccinations were 17 percent more
likely to be diagnosed with autism than kids who did get recommended
vaccinations.
Early symptoms of autism can vary but may include repetitive
behaviors like hand flapping or body rocking, extreme resistance to
changes in routine, and sometimes aggression or self-injury.
Behavioral, educational, speech and language therapy may help reduce
the severity of autism symptoms in some children.
The study wasn't a controlled experiment designed to prove whether
or how vaccines might cause autism.
Another drawback is the potential for some kids to have undiagnosed
autism before getting the MMR vaccine, which could make the MMR
vaccine appear linked to autism when it really isn't connected, the
study authors note. It's also possible that the onset of autism
symptoms might lead parents to skip the vaccine.
Still, the study adds to a large body of evidence showing that
vaccines don't cause autism, writes Dr. Saad Omer of Emory
University in Atlanta, co-author of an accompanying editorial.
"Any myth should be clearly labeled as such," Omer writes. "Even in
the face of substantial and increasing evidence against an MMR--autism
association, the discussion around the potential link has
contributed to vaccine hesitancy."
SOURCE: http://bit.ly/2NGPAnm Annals of Internal Medicine, online
March 4, 2019
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