COVID-19 Vaccination Reduces Risks for Pregnant People and Babies, UBC Study Shows

A major new study led by the University of British Columbia (UBC) provides clear evidence that COVID-19 vaccination protects both pregnant people and their babies from serious complications. Published in JAMA, the research analyzed nearly 20,000 pregnancies across Canada and found that vaccinated individuals were far less likely to experience severe illness or deliver prematurely.

The study showed that vaccination during pregnancy was strongly associated with lower risks of hospitalization, intensive care admission, and preterm birth. These benefits remained consistent as the virus evolved from the Delta variant to Omicron and its subsequent sublineages, which continue to circulate today. Vaccinated pregnant individuals were about 60 percent less likely to be hospitalized and 90 percent less likely to require intensive care compared with those who were unvaccinated at the time of infection. Preterm births were also reduced by 20 percent during the Delta wave and 36 percent during the Omicron wave.

Importantly, the research highlighted that receiving the COVID-19 vaccine during pregnancy, rather than before conception, provided even greater protection against preterm birth and stillbirth. “There is never a bad time to be vaccinated—whether you’re currently pregnant or planning a pregnancy,” said Dr. Elisabeth McClymont, lead author of the study and assistant professor in UBC’s department of obstetrics and gynaecology. “Our data suggest there may be added benefits to receiving the vaccine during pregnancy.”

The findings were produced through the CANCOVID-Preg surveillance network, a national collaboration led by UBC researchers. The study drew on population-based health data from nine Canadian provinces and one territory, tracking outcomes from nearly 20,000 pregnancies affected by SARS-CoV-2 between April 2021 and December 2022. Even after accounting for age, body mass index, and pre-existing conditions such as hypertension or diabetes, vaccination remained strongly linked to lower risks of hospitalization and critical care.

These results are particularly timely as vaccine guidance for pregnant people continues to evolve. While the U.S. Advisory Committee on Immunization Practices (ACIP) recently did not include a specific recommendation for COVID-19 vaccination during pregnancy in its updated adult immunization schedule, public health authorities in Canada and the World Health Organization continue to strongly advise vaccination for pregnant individuals. Dr. Deborah Money, professor of obstetrics and gynaecology at UBC and senior author of the study, emphasized that the evidence is clear: COVID-19 vaccination is safe, effective, and crucial for protecting maternal and newborn health.

Beyond the immediate benefits, the study reinforces the importance of including pregnant people in vaccine research and planning for future respiratory virus outbreaks. Pregnancy is a unique period of vulnerability but also an opportunity for prevention. Vaccination during this time can significantly reduce risks for both mother and baby, while also contributing to broader public health outcomes.

The research was funded by the Public Health Agency of Canada through the COVID-19 Immunity Task Force, the Canadian Institutes of Health Research, and the BC Women’s Health Foundation. By providing robust, population-level data, this UBC-led study offers critical guidance for care providers, policymakers, and pregnant people, underscoring that COVID-19 vaccination is a vital step for safe pregnancies and healthier newborns.