Placental transfer of antibody and its relationship to vaccination in pregnancy

Purpose of review Vaccination in pregnancy boosts maternal vaccine-specific antibody concentration and therefore increases transplacental transfer of antibody to optimize protection of the infant. The purpose of this review is to describe what is known about placental transfer of antibody in the context of vaccination in pregnancy, focussing on the recent literature and areas of debate, particularly about the timing of vaccination. Recent findings There is a debate about the timing of pertussis vaccination in pregnancy with some studies reporting that vaccination in the third trimester results in higher pertussis antigen-specific IgG concentrations in cord blood and others finding that the concentration is higher following vaccination in the second trimester. The impact of timing of vaccination on antibody avidity in cord blood has also been investigated and one study suggests that avidity may be increased following vaccination at 27-30(+6) gestational weeks compared with later vaccination. Summary Understanding placental transfer of antibody is vital in informing maternal vaccination strategy. There has been recent research about the timing of pertussis vaccination in pregnancy that has implications for the timing of both current and future vaccines to be used in pregnancy.