Maternal immune response and placental antibody transfer by trimester of COVID-19 vaccination

The study characterizes the immune response induced by the three COVID1-9 vaccines, Ad26.COV2.S, mRNA-1273 or BNT162b2 vaccination in pregnant individuals. To further understand the protective effect on the baby, we also evaluated transplacental antibody transfer by profiling maternal and umbilical cord blood in 175 maternal-neonatal dyads. These analyses reveal vaccine-dependent and trimester-dependent antibody response in the mother and fetus, with higher titers and functions by mRNA vaccines, and an increased maternal immune response from the first and third trimester of vaccination. These results provide novel insight into the impact of platform and trimester of vaccination on maternal humoral immune response and transplacental antibody transfer.