SARS-CoV-2 in pregnancy and possible transfer of immunity: assessment of peripartal maternal and neonatal antibody levels and a longitudinal follow-up

Objectives: In the current Severe Acute Respiratory Distress Coronavirus 2 (SARS-CoV-2) pandemic there is still great uncertainty about the effects of an infection in pregnancy especially regarding a possible fetal transmission of antibodies to SARS-CoV-2 and the longevity of this immunity.

Methods: Sixteen women who were infected with SARS-CoV-2 during pregnancy and their offspring were included. The antibody response to SARS-CoV-2 was measured in mother and umbilical cord blood peripartum and in a follow-up examination 6-11 weeks after birth. Medical history, symptoms regarding SARS-CoV-2, obstetric and neonatal information were queried following recommendations by the WHO.

Results: A total of 73% of the women and one third of the infants developed antibodies to SARS-CoV-2 spike (S) protein receptor binding domain (RBD), with a long interval between infection and birth proving favorable for a transplacentar transfer of antibodies to the neonates. All infants showed declining or vanishing antibody-titers in the follow-up examination, while the titers of their mothers were stable or even increased.

Conclusions: Our results demonstrate that transplacental transfer of SARS-CoV-2-specific antibodies is possible, but also indicate that the immunity that may be gained as a result might decrease in newborns postpartum. This provides important evidence that could be useful for further studies covering vaccination during pregnancy.