There could be a correlation between maternal immunization with inactivated influenza vaccine, and reduced risk of prematurity and the baby being small for gestational age, according to a study published in this week’s PLoS Medicine.
Led by Saad B. Omer from Emory University Rollins School of Public Health in Georgia, researchers analyzed 4,168 mothers and babies from a dataset provided by the Georgia Pregnancy Risk Assessment Monitoring System.
Scientists studied the relationship between the influenza vaccine during any trimester of pregnancy and the baby being premature or small for gestational age.
They found that babies born during the influenza season (October–May) and whose mothers were vaccinated against influenza during pregnancy, were less likely to be premature compared with infants of unvaccinated mothers born in the same period.
Compared to newborns of unvaccinated women, babies of vaccinated mothers had lower risk of being small for gestational age during a period of widespread influenza activity, but researchers did not find a significant difference regarding smaller size during the other seasons.
The observational study shows there is a correlation between influenza vaccination and reduced risk of prematurity, however it doesn’t demonstrate a causal link.
According to study authors: "Studies in other populations, particularly randomized controlled trials, are needed to confirm our results.”