Influenza in Pregnancy: Prevention and Treatment: ACOG Committee Statement No. 7

Maternal Immunizations: Past, Present, and Future

Maternal vaccines during pregnancy offer crucial protection against infections for both the pregnant person and their newborn. Vaccines against influenza, pertussis, coronavirus disease 2019, and respiratory syncytial virus are routinely recommended by the Centers for Disease Control and Prevention to safeguard pregnant women and their infants from potentially severe complications. Administering these vaccines during pregnancy helps transfer protective antibodies from the mother to the baby, enhancing immunity during the vulnerable early months of life. Extensive research supports the safety and efficacy of maternal vaccines, with numerous studies demonstrating their protective benefits for both pregnant people and newborns.

Pathogenesis of viral infections during pregnancy

SUMMARYViral infections during pregnancy are associated with significant adverse perinatal and fetal outcomes. Pregnancy is a unique immunologic and physiologic state, which can influence control of virus replication, severity of disease, and vertical transmission. The placenta is the organ of the maternal-fetal interface and provides defense against microbial infection while supporting the semi-allogeneic fetus via tolerogenic immune responses. Some viruses, such as cytomegalovirus, Zika virus, and rubella virus, can breach these defenses, directly infecting the fetus and having long-lasting consequences. Even without direct placental infection, other viruses, including respiratory viruses like influenza viruses and severe acute respiratory syndrome coronavirus 2, still cause placental damage and inflammation. Concentrations of progesterone and estrogens rise during pregnancy and contribute to immunological adaptations, placentation, and placental development and play a pivotal role in creating a tolerogenic environment at the maternal-fetal interface. Animal models, including mice, nonhuman primates, rabbits, and guinea pigs, are instrumental for mechanistic insights into the pathogenesis of viral infections during pregnancy and identification of targetable treatments to improve health outcomes of pregnant individuals and offspring.

Perinatal COVID-19: Implications for care of the newborn

The maternal/newborn dyad presents special challenges to infection management. Early in the COVID-19 pandemic, lack of information regarding SARS-CoV-2 transmission and virulence made it difficult to develop appropriate care guidance when pregnant persons had COVID-19 at the time of presentation for childbirth. We will review the considerations for the parturient, newborn, and care team, and describe the evolution of perinatal COVID management guidance.

Understanding New Recommendations for Respiratory Syncytial Virus Prevention in Pregnancy

Respiratory syncytial virus (RSV) is a significant cause of infant morbidity and mortality worldwide with peak hospitalization rates for RSV-mediated illnesses between 2 and 3 months of life. Until very recently, prevention strategies for RSV involved primarily passive immunization of neonates at high risk with monoclonal antibodies and promotion of breastfeeding. The Centers for Disease Control and Prevention's (CDC) Advisory Committee on Immunization Practices now recommends passive immunization of all neonates with monoclonal antibodies during RSV season, and the American Association of Pediatrics has endorsed this practice. The U.S. Food and Drug Administration (FDA) recently approved a vaccination for RSV in pregnancy. The CDC's Advisory Committee on Immunization Practices has recently recommended RSV vaccination for all pregnant patients between 32 and 36 weeks of gestation who are anticipated to deliver during RSV season if they are not planning nirsevimab for their infants. This recommendation has been endorsed by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine. In this clinical perspective, we review the scientific evidence, potential concerns, challenges, and future considerations for RSV vaccination in pregnancy.