Association of SARS-CoV-2 Serology in Cord Blood with Maternal COVID-19 Vaccination Status: A Prospective Cohort Study

Introduction: Maternal vaccination against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) offers an opportunity to protect both pregnant women and their newborns. Understanding how vaccine timing and dosing influence transplacental antibody transfer is essential for optimising perinatal immunisation strategies. Aim: To assess the SARS-CoV-2 Immunoglobulin G (IgG) status and its association with maternal Coronavirus Disease 2019 (COVID-19) vaccination status. Materials and Methods: A prospective observational cohort study was conducted at the Department of Neonatology, Paediatrics, Swami Rama Himalayan University, Dehradun, Uttarakhand, India, from October 2021 to January 2022. The study included all 200 mothers who delivered during the study period and their neonates. Maternal SARS-CoV-2 infection and vaccination status were recorded on admission. Umbilical cord blood was collected at birth and IgG was assessed. Neonates born to mothers with confirmed infection underwent polymerase chain reaction testing. Primary analysis compared Cord blood IgG concentrations across vaccination subgroups and examined associations with the number of doses, interval since vaccination, and gestational age at delivery. The Kruskal-Wallis test was used to determine statistically significant differences between groups. A two-tailed p-value