Updated COVID-19 vaccines recommended for fall boosters, Canadian vaccine advisors say
The country’s national vaccine advisers are recommending that Canadians receive another COVID-19 booster shot this fall, with updated vaccines expected in the coming months.
The next round of vaccines will likely be monovalent, meaning they will specifically target the Omicron family of sublines that are still circulating worldwide, the National Advisory Committee on Immunization (NACI) said Tuesday.
“An additional dose using the latest vaccine formulations will be an important tool to not only build protection against serious diseases that decline over time, but also to protect against the currently circulating SARS-CoV-2 variants,” said Canada’s Chief Public Health Officer, Dr. Theresa Tam, said in a statement.
“This extra dose is especially important for people who are at increased risk of a COVID-19 infection or serious illness.”
In May, a World Health Organization advisory group suggested it would be ideal to focus on a monovalent shot aimed at XBB.1 and its offshootsinstead of a bivalent vaccine targeting both new and old strains of the coronavirus, which was the last booster to be rolled out in Canada.
“Manufacturers have indicated that new COVID-19 vaccine formulations are in development and products are on the way,” the Canadian vaccine advisors wrote, adding that booster doses expected before the fall will be “updated to target more recent, immune-evasive SARS-CoV-2. variants.”
The virus that causes COVID-19 continues to mutate as testing decreases, raising concerns that a new variant could explode before it is detected and tracked. But Canadian laboratories are on the case.
The mRNA-based vaccines remain the preferred COVID-19 vaccine product, the recommendations continued.
Dr. Allison McGeer, an infectious disease specialist at Toronto’s Mount Sinai Hospital, says NACI’s recommendations were expected.
“People have been thinking really hard about… what’s going to give us the best protection.”
But McGeer said this advice could still change depending on the disease trajectory, infection level and whether new strains emerge in the coming months.
Who should get vaccinated – and when?
NACI’s new guidelines say Canadians should wait to get a booster at least six months after a previous vaccine dose or known SARS-CoV-2 infection — whichever came later. That’s because research shows that the injections are more effective when away from an active infection or previous vaccination. as CBC News has previously reported.
A Canadian for example, a study suggests that protection against infection from two doses of the Pfizer vaccine peaks when the first and second injections are spread, from about 80 percent after a few weeks to more than 90 percent after four months.
While NACI recommends that everyone should receive a dose of a new vaccine, it specifically recommends that people at higher risk of serious illness receive the booster dose.
Vulnerable groups at higher risk include:
- Adults 65 and older.
- Long-term care and cohabiting residents.
- People with underlying medical conditions that put them at higher risk of serious illness.
- People who are pregnant.
- First Nations, Métis and Inuit people.
- People from racialized and other communities who deserve equality.
- People who provide essential community services.
Dr. Isaac Bogoch, an infectious disease specialist at the University Health Network in Toronto, agreed that continued vaccination remains essential for high-risk groups.
“The challenge is, what does everyone else do? It’s clear who is at risk for a bigger infection…but what do you do for everyone?” he said.
“One of the challenges we’re going to face is the uptake of vaccination in the other groups. Will people come for that booster vaccine?”
More targeted communication strategies will be helpful in the future to reach people with different levels of risk, Bogoch added.
Federal numbers show that the vast majority of Canadians have been vaccinated against COVID-19 to date, with more than 80 percent of the population having completed their primary vaccinations. But interest in getting additional injections has waned over time — less than six percent of Canadians received a repeat dose or completed their primary series in the past six months.
Protection against vaccination, infection decreases ‘over time’
NACI continues to recommend COVID-19 vaccination for anyone who has not yet been immunized, including those over the age of five and children six months to five years old. The currently available bivalent vaccines could be used for a primary vaccine series for either age group, the advisers noted.
NACI also pointed to the higher levels of protection against serious illnesses afforded by hybrid immunity – when people are both vaccinated and previously infected – as opposed to vaccination alone or previous infection alone.
“For this reason, an additional dose of vaccine from this fall is especially important for those who have not been previously infected and are only protected against vaccination,” the guideline said.
“However, even with hybrid immunity, protection against infection will decrease over time and the duration of protection against serious disease varies between studies and is unknown in the context of currently circulating variants.”
The World Health Organization declared that COVID-19 is no longer a “global health emergency,” but with strained health systems and persistently high deaths, the virus remains a concern.
While people may be tired of getting COVID-19 shots, McGeer said it’s important to remember that “you’re less likely to get sick and less likely to die if you choose to get vaccinated.”
When it comes to whether new COVID-19 vaccinations will be offered year-over-year similar to the flu, McGeer said it’s “too early to say”.
Will there be another wave?
While it’s unclear if Canada will see an increase in COVID-19 cases in the fall, NACI says it’s usually a time when other respiratory illnesses are on the rise, such as the flu and RSV.
“We know that more COVID will appear on the horizon in the fall and winter months,” said Bogoch.
As a result, NACI recommends that people get vaccinated to protect those who are vulnerable to other diseases and to avoid overburdening the healthcare system.
In the latest recommendations, the committee says modeling predicts that a fall vaccine dose could “avoid thousands of hospitalizations and deaths across the country over the next year.”
It’s unclear exactly when the new doses will become available, but NACI says it will continue to review the latest information on the vaccine and make updated recommendations as needed.
