SARS-CoV-2 Vaccination Before and During Pregnancy and Prevention of Infant COVID-19 Infection

BACKGROUND SARS-CoV-2 vaccination during pregnancy reduces COVID-19 risk in infancy. Whether maternal vaccination before pregnancy similarly protects infants against COVID-19 is unknown. METHODS We examined the effectiveness of maternal messenger RNA SARS-CoV-2 vaccination before and during pregnancy in preventing COVID-19 in infants aged 0–6 months born between July 1, 2021, and June 30, 2023, at Kaiser Permanente Northern California. Maternal vaccination status was categorized as vaccinated du