Use of influenza vaccines during pregnancy
As the risk of influenza disease is increasingly recognized among pregnant women and a growing body of evidence supports the benefits to infants of maternal vaccination, the committee reviewed the safety data available for influenza vaccines derived from clinical trials, observational studies, and spontaneous reporting. The data confirm the safety of non-adjuvanted trivalent inactivated seasonal influenza vaccines in pregnancy. For example in the USA outcomes of pregnancy were assessed in 3719 vaccinated pregnant women compared with 45 866 controls in the Vaccine Safety Datalink during the period 1997–2002. From 1990–2009, an estimated 11.8 million pregnant women were vaccinated in the USA. In addition, a review of spontaneous reports found no maternal deaths, no unexpected pattern of adverse pregnancy events or fetal outcomes, and no increased risk of adverse pregnancy outcomes when compared to background rates. Extensive evaluation during the 2009 influenza A(H1N1)pdm09 pandemic supported the safety of adjuvanted and non-adjuvanted influenza vaccines when used in pregnant women; overall, the safety profile was comparable to seasonal influenza vaccine in non-pregnant adults, and there was no evidence of teratogenicity or any other negative impact on pregnancy outcomes. In addition, preliminary data from a few studies of influenza vaccine in pregnant women have confirmed not only the benefit of providing protection in this vulnerable population, but positive effects in their infants, including the reduction of low birth weights, and a significant decrease in influenza-related pneumonia in young children.