Impact of maternal immunization on influenza hospitalizations in infants

• DOI: 10.1016/j.ajog.2011.02.042
• Publication Date: 2011-02-24T13:43:46Z
• Authors: Katherine A. Poeh...; Peter G. Szilagyi; Mary A. Staat; Beverly M. Snively; Daniel C. Payne; Carolyn B. Bridges; Susan Y. Chu; Laney S. Light; Mila M. Prill; Lyn Finelli; Marie R. Griffin; Kathryn M. Edwards
• Keywords: Routine immunization

We sought to determine whether maternal vaccination during pregnancy was associated with a reduced risk of laboratory-confirmed influenza hospitalizations in infants <6 months old. Active population-based, laboratory-confirmed influenza surveillance was conducted in children hospitalized with fever and/or respiratory symptoms in 3 US counties from November through April during the 2002 through 2009 influenza seasons. The exposure, influenza vaccination during pregnancy, and the outcome, positive/negative influenza testing among their hospitalized infants, were compared using logistic regression analyses. Among 1510 hospitalized infants <6 months old, 151 (10%) had laboratory-confirmed influenza and 294 (19%) mothers reported receiving influenza vaccine during pregnancy. Eighteen (12%) mothers of influenza-positive infants and 276 (20%) mothers of influenza-negative infants were vaccinated (unadjusted odds ratio, 0.53; 95% confidence interval, 0.32-0.88 and adjusted odds ratio, 0.52; 95% confidence interval, 0.30-0.91). Infants of vaccinated mothers were 45-48% less likely to have influenza hospitalizations than infants of unvaccinated mothers. Our results support the current influenza vaccination recommendation for pregnant women.