Can Maternal COVID-19 Vaccination Protect Newborns?

In this case control study, 537 case infants younger than 6 months of age who were admitted to the hospital with COVID-19 were compared to 512 control infants who were hospitalized for other reasons; 16% of the case infants and 29% of the control infants had been born to mothers who had been fully vaccinated against COVID-19 during the pregnancy. The effectiveness of maternal vaccination against infant hospitalization for COVID-19 was 52% overall, 80% during the Delta variant period, and 38% during the Omicron variant period. Effectiveness increased when the vaccine was received after 20 weeks of pregnancy.