Pandemic Influenza and Pregnant Women: An Overview of Influenza Vaccination during Pregnancy and Impact on Pregnancy Outcomes

Introduction: Evidence of the Influenza vaccine’s effectiveness and safety in pregnancy is critical to the decision making process of health care providers. We aimed to review the available evidence on the effectiveness and safety of influenza vaccination during pregnancy and the impact on pregnancy outcomes.Materials and Methods: In this overview, two independent researchers have selected articles that reported the effectiveness and safety of influenza vaccination during pregnancy for pregnant women and their fetus in the Scopus, EMBASE, Cochrane library, Web of Science, CINAHL, Medline databases, and Google Scholar search engine, without time restrictions up to November ۲۰۲۲.Results: Based on the available evidences, pregnant women are more at risk of serious illness due to influenza compared to non-pregnant women. Influenza vaccine is the best way to protect pregnant women and their infants from influenza and prevent possible influenza-associated pregnancy complications. While vaccination during pregnancy is a safe and cost-effective method, it also provides neonatal protection against influenza due to the partial transplacental transfer of protective antibodies. There was no evidence of associations between influenza vaccination administered at any time in pregnancy and adverse pregnancy or fetal outcomes including premature birth, spontaneous abortion, congenital anomalies, shortened gestation, gestational diabetes, chorioamnionitis or gestational hypertensive disorders, and fetal death. In addition, influenza vaccination during pregnancy reduced a pregnant woman's risk of pre-delivery hospitalisation with influenza like illness by around ۳۹%.Conclusion: Administration of an inactivated influenza vaccine during pregnancy is safe for both the mother and their fetus, and is recommended for all pregnant women. There was no evidence of associations between influenza vaccination and maternal complications or adverse fetal outcomes.

Keywords:

Adverse events , Influenza vaccination , Pregnant women , Outcomes