Do the Benefits of a Flu Shot During Pregnancy Go Beyond Mom?

Influenza vaccination is not immunogenic in children younger than 6 months old. A possible alternative strategy for protecting these infants is to vaccinate their mothers during pregnancy, with the idea that maternal antibodies will cross the placenta. In a retrospective cohort study at four managed care organizations, investigators matched 3160 infants born to mothers who had been given influenza vaccine during pregnancy (exposed) with 37,969 infants born to unvaccinated mothers (unexposed). The infants were followed for acute respiratory illnesses requiring outpatient, emergency department, or inpatient visits during peak influenza weeks and other seasonal periods.

The incidence of medically attended acute respiratory illnesses in these in…