Immunology of pregnancy and vaccination: importance, recommended vaccines, and appropriate timing of administration

Abstract

During pregnancy, the maternal immune system dynamically adapts, balancing tolerance to paternal-fetal antigens with active protection against pathogens. Maternal immunization is a fundamental public health strategy that provides protection to pregnant women, fetuses, and newborns. During pregnancy, the risk of morbidity and mortality associated with vaccine-preventable diseases increases. Maternal immunization takes advantage of the mother's natural ability to generate antibodies that cross the placenta (immunoglobulin A (IgG), which is secreted in breast milk). Inactivated vaccines, such as those recommended for pertussis
(Tdap), influenza, and COVID-19, have been shown to be safe and effective during pregnancy. However, vaccine coverage is low in many regions, driven primarily by vaccine hesitancy and concerns about safety for the infant. Healthcare professionals
play a key role in improving uptake through clear and proactive communication.