To assess the association between neonatal SARS-CoV-2 antibody level at delivery and infant COVID-19 infection under age 6 months, and to identify predictive factors for neonatal antibody level at delivery.

This prospective observational study was conducted at the Rabin Medical Center, Israel. Mothers were enrolled from September 2021 to mid-February 2022, prior to transfer to the delivery room, and followed at the Maternity and Infant Ward. The study was approved by the institutional ethics committee (RMC- 0275-21). Written informed consent was obtained from the participating mothers. Inclusion criteria included maternal recipient of at least one dose of the BNT162b2 mRNA COVID-19 vaccine or prior microbiologically-confirmed natural COVID-19 infection. Exclusion criteria included (a) preterm birth at <34 weeks gestation; (b) congenital or acquired immune deficiency, including recipient of biological agents during the prior year to enrolment.

Inclusion Criteria:

included maternal recipient of at least one dose of the BNT162b2 mRNA COVID-19 vaccine or prior microbiologically-confirmed natural COVID-19 infection

Exclusion Criteria:

(a) preterm birth at <34 weeks gestation; (b) congenital or acquired immune deficiency, including recipient of biological agents during the prior year to enrolment.

Mothers prior to transfer to the delivery room and followed at the Maternity and Infant Ward

According to ethics committee approval.