Researchers focused on those with rheumatoid arthritis, lupus, inflammatory bowel disease, multiple sclerosis and other immune-mediated inflammatory diseases

New research findings provide solid evidence that annual COVID-19 vaccine booster doses continue to be advisable for certain immunocompromised people, researchers at McGill University say.

The researchers looked at how often people with immune-mediated inflammatory diseases (IMIDs) got COVID-19 despite having received at least three doses of an mRNA COVID-19 vaccine. IMIDs – including rheumatoid arthritis, lupus, inflammatory bowel disease and multiple sclerosis – affect more than seven million Canadians. The medications they take often weaken their vaccine responses, increasing their vulnerability to infection.

Published in Vaccines, the study found that 15 per cent of IMID patients contracted COVID-19 at least once during the year-long study, but that patients with higher levels of a specific antibody, which is produced in response to the vaccine, had lower chances of getting infected.

“Our findings highlight why booster doses are so important, because immunity naturally wanes over time, and maintaining those high antibody levels may be key to protecting against infection,” said senior author Sasha Bernatsky, James McGill Professor in McGill’s Divisions of Rheumatology and Clinical Epidemiology and a senior scientist at the Research Institute of the McGill University Health Centre.

Past COVID-19 infections did not clearly affect the risk of a breakthrough case in the study.

“This is an important takeaway for those who assume they have lasting immunity after contracting the virus,” Bernatsky said.