Seroprevalence of SARS-CoV-2 immunoglobulins in pregnant women and neonatal cord blood from a highly impacted region.

There is inadequate screening for SARS-COV-2 during pregnancy. We aimed to determine the impact of maternal and neonatal cord blood SARS-COV-2 antibodies and placental transfer ratios in a region with a low screening plan. We performed a blind study in one of the SARS-CoV-2 epicenters in South America. 32% of pregnant women were serological positive. Importantly, there is an efficient passive immunization of the fetus to SARS-CoV-2. We report high incidence of SARS-CoV-2 infection during pregnancy, which is higher than officially reported. Therefore the need of active immunization to enhance maternal protection and fetal passive immunization.