Neonatal antibody levels and treatment outcomes following maternal vaccination among NICU infants exposed to COVID-19 during pregnancy

Abstract

The COVID-19 pandemic has profoundly affected maternal and child health worldwide, with pregnant women being particularly vulnerable to complications. Vaccination during pregnancy has been shown to generate protective antibodies offering passive immunity to neonates, though concerns remain about potential risks. This study aims to compare infants, specifically a high-risk NICU cohort, exposed and not exposed to COVID-19 vaccination in utero by evaluating their antibody levels, clinical and laboratory characteristics, and treatment outcomes. A prospective study was conducted from January to December 2022 at the Neonatal Intensive Care Unit (NICU) of Vietnam National Children’s Hospital. Neonates under 30 days old with respiratory distress born to mothers with COVID-19 were divided into vaccinated ( n = 75) and unvaccinated groups ( n = 46). Data on maternal vaccination, clinical symptoms, laboratory findings, and treatment outcomes were collected and analyzed. Neonates born to vaccinated mothers had significantly higher anti-spike (anti-S) antibody levels than those born to unvaccinated mothers (median [IQR]: 2929.00 [1063.00–7817.00] U/mL vs. 335.00 [153.65–3000.50] U/mL, p = 0.007). This association remained significant after adjustment for gestational age and birth weight. Clinical manifestations, most laboratory parameters, and neonatal outcomes, including mortality, duration of mechanical ventilation, and length of hospital stay, were comparable between the two groups. Gestational age was lower in the vaccinated group (34.96 ± 4.03 weeks vs. 36.48 ± 3.77 weeks, p = 0.042). This study suggests that maternal COVID-19 vaccination during pregnancy may enhance neonatal humoral immunity, as evidenced by significantly higher anti-S antibody levels in newborns. This association remained significant after adjustment for gestational age and birth weight. Maternal COVID-19 vaccination was not associated with adverse neonatal clinical or laboratory findings, nor with adverse neonatal outcomes. The observed difference in gestational age raises questions that warrant further large-scale investigation.