Overview
- Vaccinated pregnant people had roughly 60% lower risk of hospitalization and about 90% lower risk of intensive care admission compared with those unvaccinated at infection.
- Preterm birth risk fell by about 20% during the Delta wave and 36% during the Omicron wave, based on deliveries before 37 weeks.
- Receiving the vaccine during pregnancy was associated with even fewer preterm births and with reduced stillbirth rates versus vaccination only before pregnancy.
- The analysis drew on nearly 20,000 SARS-CoV-2–affected pregnancies from April 5, 2021, to December 31, 2022, across British Columbia, Alberta, Manitoba, Ontario, Quebec, New Brunswick, Prince Edward Island, Nova Scotia, and Yukon.
- Researchers say the results should inform guidance for maternal vaccination as U.S. recommendations have shifted this year, including no pregnancy-specific ACIP endorsement and related litigation from leading medical groups.