Maternal vaccination for the prevention of influenza: current status and hopes for the future

Abstract

Influenza is an important cause of morbidity and mortality among pregnant women and young infants, and influenza infection during pregnancy has also been associated with adverse obstetric and birth outcomes. There is substantial evidence - from randomized trials and observational studies - that maternal influenza immunization can protect pregnant women and their infants from influenza disease. In addition, there is compelling observational evidence that prevention of influenza in pregnant women can also protect against certain adverse pregnancy outcomes, including stillbirth and preterm birth. In this article we will review and evaluate the literature on both the burden of influenza disease in pregnant women and infants, as well as the multiple potential benefits of maternal influenza immunization for mother, fetus, and infant. We will also review key clinical aspects of maternal influenza immunization, as well as identify remaining knowledge gaps, and discuss avenues for future investigation.

Keywords: Influenza; infant; maternal immunization; pandemic; pregnancy; preterm birth; seasonal; stillbirth; vaccine.

Figure 1

Odds ratios for any cardiopulmonary event during influenza season among women aged 15–44 years in the Tennessee Medicaid program, by pregnancy status and stage of gestation (by week), 1974–1993. Error bars represent 95% confidence intervals. Figure adapted from data in Table 2 in Neuzil et al [34].