SARS-CoV-2 breakthrough infection during pregnancy preferentially elicits IgG4 response and enhanced placental-transfer
Description
Emerging SARS-CoV-2 variants and waning humoral immunity have led to increased occurrences of breakthrough infection. Pregnant individuals and neonates are particularly vulnerable to adverse outcomes associated with COVID-19. We aimed to evaluate the maternal anti-SARS-CoV-2 IgG response and the placental transfer of antibodies to the fetus following breakthrough infection, infection in unvaccinated participants, and vaccination in the absence of infection during pregnancy. Pregnant patients were enrolled at Oregon Health & Science University and assigned to three cohorts based on infection and vaccination status. Receptor-binding domain (RBD) and nucleocapsid protein (NP) specific IgG endpoint titers (EPT) and optical density (OD) values were determined via ELISA longitudinally in maternal blood and breastmilk, and at delivery in paired maternal, umbilical cord, and newborn blood. With the associated data, we characterized the anti-SARS-CoV-2 antibody response longitudinally in maternal blood and breastmilk. Additionally, through comparisons of maternal antibody titers at delivery to matched umbilical cord blood and newborn blood collected within 24 hours of birth, we observed patterns of total IgG and subclass specific placental-transfer differentiated by maternal vaccination and infection status