Tracking the Sequelae of 2009 Pandemic H1N1 Influenza Vaccination During Pregnancy

Routine influenza immunization is recommended for all pregnant women, to protect their own health as well as that of their neonates (who cannot be immunized until age 6 months). Investigators in Ontario evaluated health outcomes among 31,000 children whose mothers received the 2009 pandemic H1N1 vaccine during pregnancy compared with 72,000 children in the same birth cohort whose mothers were not immunized.

Likelihood of upper and lower respiratory infections, otitis media, infectious diseases, malignancy, sensory disorders, inpatient health services, pediatric chronic conditions, and death was similar among children of immunized and unimmunized women. Incidence of asthma was 5% higher and of gastrointestinal infections was 6% lower among ch…