Maternal immunization and malaria in pregnancy

Malaria in pregnancy is a major cause of poor outcomes for both mother and fetus, and malaria-induced low birth weight (LBW) may kill nearly 400,000 African infants each year. The hallmark of pregnancy malaria due to Plasmodium falciparum is the sequestration of infected erythrocytes (IEs) in the placenta. Malaria can suppress responses to immunogens, and placental malaria can impair materno-fetal antibody transfer, potentially reducing the benefits of maternal immunization strategies. Parasites infecting the placenta have been shown to have distinct adhesive and antigenic features. Women become resistant to pregnancy malaria over successive pregnancies as they acquire antibodies that recognize placental parasites, suggesting that a vaccine is feasible. Serologic evidence indicates that the target for such a vaccine is antigenically conserved, and surface proteins expressed by placental parasites have been identified as vaccine candidates. Because malaria suppresses vaccine responses and reduces the transfer of maternal antibodies to the fetus, the prevention of pregnancy malaria may benefit maternal immunization strategies that protect neonates from infections other than malaria.