We’ve been sharing the planet with SARS-CoV-2 for more than three years now, but the science and recommendations for how to best protect against the virus and its variants are still constantly evolving.
In the latest major update to those recommendations, the World Health Organization (WHO)’s Strategic Advisory Group of Experts on Immunization (SAGE) said last week it no longer “routinely recommends” follow-up COVID-19 boosters for people with a medium or low risk of developing severe illness from the virus. Canadian health officials are, for the most part, echoing that message.
“Updated to reflect that much of the population is either vaccinated or previously infected with COVID-19, or both, the revised roadmap re-emphasizes the importance of vaccinating those still at risk of severe disease,” SAGE chair Dr. Hanna Nohynek said in a media release issued March 28.
“Countries should consider their specific context in deciding whether to continue vaccinating low-risk groups, like healthy children and adolescents, while not compromising the routine vaccines that are so crucial for the health and well-being of this age group.”
SAGE defines three priority-use groups for COVID-19 vaccination – high, medium, and low – based on a balance of cost-effectiveness and risk of severe disease or death.
The high-priority group includes seniors, younger adults with significant comorbidities such as diabetes and heart disease, adults and children older than six months with immunocompromising conditions, pregnant people and front-line health-care workers.
According to Canadian immunologist Matthew Tunis, the new SAGE guidance is similar to spring booster recommendations the Public Health Agency of Canada’s National Advisory Committee on Immunization (NACI) made several weeks earlier.
“Our assessment is that there’s a high degree of concordance or overlap between what the WHO is recommending that every country considers and what NACI has been recommending for COVID-19 boosters,” Tunis, who serves as NACI’s executive secretary, told CTVNews.ca in a phone interview on Tuesday.
NACI recommends that high-risk Canadians receive booster shots this spring, even if they were boosted in the fall.
That group includes all adults 80 years of age and older; adults 65 to 79 years old, especially if they have never been infected with COVID-19; adults living in long-term care homes and other aggregate living settings for seniors or those with complex medical care needs; and people over 18 who are moderately to severely immunocompromised due to an underlying condition or ongoing treatment.
Healthy, fully vaccinated individuals who have received one dose of a COVID-19 vaccine booster can skip the spring vaccination campaign. Those who have received a primary course of a COVID-19 vaccine but haven’t received their first booster dose should get boosted as soon as possible.
As for when low-risk Canadians should get their next boost, Tunis said they can technically do so six months after their last dose, according to the Canadian Immunization Guide, but that it’s better if they wait for further guidance from NACI or consult their provincial booster recommendations first.
For now, he said, the committee is still trying to determine whether COVID-19 boosters for the general population should be rolled out as a seasonal, annual or as needed program in the future.
“What we are seeing…is that hybrid immunity, which is achieved by vaccination in those who have a history of infection as well, is proving to be very stable to prevent severe disease,” Tunis said. “But everyone is watching closely to see how long all of this immunity lasts, and if there’s continued wanting, there may be a need for continual boosters.”
Even as highly contagious Omicron sub-variants have continued to spread within Canada, hospitalizations, ICU admissions and deaths have stabilized for now. During a federal COVID-19 update on March 10, Chief Public Health Officer Dr. Theresa Tam said the virus has reached a relatively steady state in Canada.
“While uncertainty remains about the seasonal patterns for COVID-19, the current trend suggests we may not see any major waves in the coming months as we prepare for a potential fall and winter surge,” Tam said. “Together with international partners, we will also continue to closely monitor the situation.”