Previous studies have reported mixed results on associations between influenza infection
during pregnancy and ASD, and none have looked at maternal vaccination, researchers
They studied records of 196,929 children from 2000-’10 and found that 3,101 (1.6%)
had been diagnosed with ASD. Among mothers, 1,400 (0.7%) had contracted influenza,
and 45,231 (23%) received the influenza vaccine during pregnancy.
After adjusting for covariates, the team concluded there was no association between
maternal influenza infection and ASD risk anytime or when broken down by trimester.
There also was no association between maternal influenza vaccination overall and ASD
risk. When broken down by trimester, “there was a suggestion of increased risk” in
the first trimester. However, the authors noted “the association was statistically
insignificant after adjusting for multiple comparisons, indicating that the finding
could be due to chance.”
“While we do not advocate changes in vaccine policy or practice, we believe that additional
studies are warranted to further evaluate any potential associations between first-trimester
maternal influenza vaccination and autism,” they wrote.
The Academy and the Centers for Disease Control and Prevention’s Advisory Committee
on Immunization Practices strongly recommend that pregnant women receive a flu shot
to protect both the mother and baby from life-threatening illness, saying the vaccine
is safe and effective.
“Pregnant women are of special concern because they are at high risk of complications
from influenza,” the Academy said in its 2016-’17 influenza policy. “Vaccination of pregnant women also provides protection for their infants, potentially
for as long as 6 months through the transplacental transfer of antibodies.”