Flu Vaccination During Pregnancy Not Linked to Autism Risk, Study Finds

Flu vaccinations during pregnancy do not seem to increase risk of autism spectrum disorders (ASDs) in children, according to a report published in JAMA Pediatrics.

The study found no connection between maternal influenza infection and vaccination and autism risk in children. Although maternal infections and fever during pregnancy have been associated with increased risk for autism spectrum disorders, no study has investigated the impact of influenza vaccination during pregnancy on ASD risk.

The study examined 196,929 children born at Kaiser Permanente Northern California from January 1, 2000 to December 31, 2010. Within the specified cohort, influenza was diagnosed in 17% of mothers and 23% received the influenza vaccination during pregnancy. Altogether, 1.6% of children in the study were diagnosed with ASD.

In light of the study’s results, the researchers found that maternal influenza infection or influenza vaccination anytime during the pregnancy was not associated with increased risk of ASD.

Trimester-specific results indicated a small increase in risk of ASDs when mothers received flu vaccinations during the first trimester. However, these associations were not statistically significant enough to provide evidence for a direct causal link and were determined to be due to chance.

The study’s cohort restricted eligibility to children who were born at the gestational age of at least 24 weeks and remained health plan members until at least 2 years of age.

Researchers examined the mothers’ medical records for influenza infections and vaccinations that occurred during the pregnancy.

Although the study’s results seem to be positive, more research will be needed on the subject to provide a definitive answer, especially since other studies have found associations between maternal infections during pregnancy and autism.

Women are encouraged to receive their flu immunizations while pregnant because of the high risks that influenza infections pose to newborns.