Infants born to mothers who were vaccinated against influenza are half as likely to be hospitalized for flu than those of mothers not vaccinated, found a study by researchers at Wake Forest Baptist College. It was the first laboratory-based study to reach this conclusion. The Advisory Committee on Immunization Practices (ACIP) currently recommends influenza vaccination for anyone older than 6 months of age, but specifically singles out target groups (including pregnant women) who have a greater risk of influenza-related complications.
Because flu vaccines are not approved for children younger than 6 months, researchers wanted to assess whether vaccinating pregnant mothers offered any health benefits to newborn babies. They analyzed data from the Centers for Disease Control and Prevention-funded New Vaccine Surveillance Network over the course of seven flu seasons between 2002 and 2009 (before the H1N1 pandemic). The data included information about 1,510 babies hospitalized with the flu. Researchers concluded babies born to mothers who had the vaccine were 45-48% less likely to be hospitalized due to influenza.
According to the study’s lead author, Dr. Katherine Poehling:
It is recommended that all pregnant women receive the influenza vaccine during pregnancy because it is known that pregnant women have increased morbidity and mortality during pregnancy and in the immediate postpartum period if they get the flu. We also know that mothers pass antibodies through the placenta to the baby. This study showed us that receiving the influenza vaccine during pregnancy not only protects the mother, but also protects the baby in the early months of life.
Poehling said it was important not only for pediatricians, but also any doctors responsible for treating pregnant women, to understand the results of the study. “Pediatricians have been vaccinating children for a long time, but vaccine recommendations for obstetricians and gynecologists have changed over the last decade,” she said. “Everyone is having to adjust.”