Maternal Immunization

Vaccines administered to women during pregnancy can provide protection against serious infectious diseases for the mother, the child, or both. Maternal immunization boosts the concentration of maternal antibodies that can be transferred across the placenta to directly protect children too young to be immunized. In addition, indirect protection through prevention of maternal infection and breast-milk antibodies can be achieved through maternal immunization. In general, inactivated vaccines are considered safe for pregnant women and fetuses, whereas live attenuated vaccines are avoided due to the theoretical potential risk of infection to the fetus. However, the potential risks of vaccines need to be weighed against the risk of the disease itself and the benefits of vaccination in terms of protection of the mother and child against infectious disease. Tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap); influenza; coronavirus disease 2019 (COVID-19); and respiratory syncytial virus (RSV) vaccines are routinely recommended for all pregnant women in the United States. Maternal immunization has the potential to improve the health of mothers and young children; therefore, other diseases of relevance during this period are now targets of active research and vaccine development, including group B streptococcus (GBS). Similarly, several vaccines can be administered during pregnancy in special circumstances when maternal health, travel, or other special situations arise. This article reviews the current recommendations for vaccination of women during pregnancy.