COVID shot reduces risk of severe illness, premature birth in pregnancy, study finds

A pregnant woman stands for a portrait in Dallas, Thursday, May 18, 2023. THE CANADIAN PRESS/AP, LM Otero (LM Otero)

A new study says the COVID-19 vaccine protects pregnant women from getting severely ill or giving birth prematurely.

Researchers with the Canadian Surveillance of COVID-19 in Pregnancy (CANCOVID-Preg) program, led by the University of BritishColumbia analyzed public health and clinical records of 19,899 pregnant people diagnosed with COVID between April 5, 2021 and Dec. 31, 2022.

That time period covered infections with both Delta and Omicron variants in eight provinces and one territory.

Dr. Deborah Money, senior author of the paper published Monday in JAMA, said having such a large study “robustly” confirms the benefit of COVID-19 vaccination for pregnant women.

“Women are protected from hospitalization and have lower rates of critical care unit admission and have lower rates of preterm birth, which is associated with the COVID infection,” said Money, who is a professor of obstetrics and gynecology at UBC, in an interview on Monday.

The researchers found that vaccinated pregnant women were about 60 per cent less likely to be hospitalized and 90 per cent less likely to need intensive care compared to those who were unvaccinated when they got the virus.

The risk of premature birth was 20 per cent lower during the Delta wave and 36 per cent lower during the Omicron wave among women who were vaccinated.

Money said even though COVID-19 isn’t circulating as widely in Canada right now, women who are planning to become pregnant or who are pregnant would still benefit from getting the shot.

“It’s still early in what we call the respiratory season,” she said.

“We are very much recommending that women take the opportunity of being protected against COVID,” she said.

A sub-analysis within the study found that COVID vaccination during pregnancy showed an even greater reduction in the rates of premature birth than when getting the shot before becoming pregnant.

“Any time is a good time to be vaccinated,” Money said.

Women who are planning to become pregnant who are overdue for a COVID-19 shot or booster should go ahead and get it, she said.

“We’re not advising women to delay (getting) the vaccine until they’re pregnant,” Money said.

“But if it turns out that they become pregnant and they haven’t been recently boostered, getting the vaccine in pregnancy is both safe, but also additionally potentially beneficial.”

The research captured data from pregnancies in BritishColumbia, Alberta, Manitoba, Ontario, Quebec, New Brunswick, Prince Edward Island, Nova Scotia and Yukon.

Money said that although influenza wasn’t part of the study, that virus is spreading now and pregnant women should get a flu shot to protect themselves and their baby.

This report by Nicole Ireland, The Canadian Press, was first published Dec. 15, 2025.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.