Objective: 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.
Methods: 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.
Results: The group with ≥90 days between infection and delivery showed a higher antibody transfer rate than the <90 days group(β= 0.33, 95%CI: 0.01-0.65). Neonatal IgG titers correlated significantly with maternal titers and with maternal infections more than 90 days before delivery. Among infected pregnant women, those who had received two or three doses of vaccine before pregnancy had higher neonatal antibody titers than those who were not vaccinated (β = 57.70, 95%CI: 31.33-84.07).
Conclusion: Neonates born to pregnant women who were vaccinated before infection showed higher antibody titers than neonates of pregnant women who were not vaccinated before infection. The transfer rate is higher in pregnant women with ≥90 days from infection to delivery than in those with <90 days. These findings highlight the importance of timely maternal vaccination to optimize maternal and infant immunity.
Keywords: SARS-CoV-2; antibody transfer rate; maternal antibody; vaccinate.
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