A preliminary study on the effectiveness of maternal to neonatal transfer of antibodies against SARS-CoV-2 in the women vaccinated with heterologous CoronaVac–ChAdOx1

Abstract

The objective is to evaluate the effectiveness of placental transfer of maternally derived SARS-CoV-2 IgG antibodies after the vaccination of pregnant women with heterologous CoronaVac–ChAdOx1. Thirty pregnant women were vaccinated with CoronaVac as the first dose, followed by ChAdOx1 3 weeks later. The antibody levels in the maternal blood and in the umbilical cord blood at the time of delivery were determined. The results showed that the vaccination effectively increased antibody levels in both mothers and newborns. The antibody levels in the mothers were strongly correlated with those in the newborns (P