Deborah Lehman, MD reviewing Shakib JH et al. Pediatrics 2016 May 3.

Infants born to vaccinated mothers were more than 60% less likely than those born to unvaccinated mothers to have confirmed influenza or an influenza-like illness during the first 6 months of life.

Influenza causes the greatest morbidity and mortality at the extremes of life. Young infants are especially vulnerable, and influenza vaccine is not licensed for use before age 6 months. To determine the effect of maternal influenza vaccination during pregnancy on infant outcomes during the first 6 months of life, researchers reviewed records for nearly 250,000 mother–baby pairs born at hospitals in Utah and Idaho during influenza seasons from 2005 to 2014.

Overall, only 10% of women reported receiving influenza vaccine during the pregnancy; however, vaccine coverage increased over the study period from roughly 2% to more than 50%. There were no differences in pregnancy outcomes, including rate of prematurity and birth weight, between infants born to vaccinated women and those born to unvaccinated women. Infants born to vaccinated women had significantly lower rates of evaluation for an influenza-like illness (ILI; 1.34 vs. 3.70 per 1000), hospitalization for an ILI (0.17 vs. 1.05 per 1000), and laboratory-confirmed influenza (0.84 vs. 2.83 per 1000). There were no differences in rates of laboratory-confirmed respiratory syncytial virus infection between the two groups.

Citation(s):

Shakib JH et al. Influenza in infants born to women vaccinated during pregnancy. Pediatrics 2016 May 3; [e-pub].

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