Effects of the timing of maternal SARS-CoV-2 infection and vaccination status on placental transfer of antibodies to neonates: A cross-sectional study

•Newborns of pregnant women with combined immunity had higher antibodies.•Pregnant women, infected≥90 days predelivery, show increased antibody transfer.•Neonatal IgG antibody titers were positively correlated with maternal titers. To assess the effects of timing of maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination status on placental transfer of antibodies to neonates. In this cross-sectional study, chemiluminescence was employed to measure SARS-CoV-2 IgG antibody titers in paired maternal-infant samples from women infected during pregnancy who were vaccinated or unvaccinated. Generalized linear regression assessed factors affecting antibody transfer in infected pregnant women and neonatal titers. The group with ≥90 days between infection and delivery showed a higher antibody transfer rate than the