Want a COVID-19 booster? Experts say most Canadians should wait for updated shots
Vulnerable groups could benefit from more frequent boosting than broader public
It's been close to a year since Edwina Thomas last had a COVID-19 vaccine, and in a couple of weeks, she'll be back to her job as a school librarian right while infection rates are rising again.
The 59-year-old Dartmouth, N.S., resident wants another booster shot — but said she was told she's not eligible for another round yet, and doesn't know when updated vaccines will arrive.
Now she feels stuck in limbo.
"I don't want to get sick, I don't want to pass it on to older family members that are immune-compromised, I don't want the children at school to be sick, I don't want it to be my fault," she told CBC News.
"I think it's just going to go through us like a tidal wave."
While the size of Canada's apparent fall COVID wave won't be clear for some time, there are early signals that cases are spiking — as drug makers such as Pfizer and Moderna are still waiting for Health Canada and other regulatory bodies to greenlight their updated shots. Those boosters, once approved, will likely start rolling out by early October, officials say.
In the meantime, how are Canadians supposed to navigate the weeks ahead?
Dr. Theresa Tam, Canada's chief public health officer, told CBC News most people should simply wait for the latest shots to become available.
The reason, several experts explained, is two-fold: First, the new boosters will be better tailored to the currently-circulating Omicron subvariants, which should help ward off infections over the fall and winter months.
Second, even without that extra dose, experts say the majority of the population has already developed longer-lasting protection against serious illness after multiple rounds of vaccination, infection, or both.
For anyone at a higher risk of severe disease, however, Tam said an earlier dose of the currently available vaccines may be beneficial if it's been more than six months since someone's last vaccination or infection.
"We do recommend people go and talk to their health provider about their own particular risk situation," she said.
What we know about fall COVID-19 boosters
Officials expect vaccine roll-outs to begin by October.
Drugmakers updating vaccines to better match current strains.
Most Canadians can consider getting another shot six months or so after their last vaccination or infection.
Anyone at a higher risk of serious illness, including older adults, pregnant individuals, people who are immunocompromised, or people with other health conditions, should talk to their health provider if they want another dose sooner.
It's considered safe to get both your COVID booster and a flu shot at the same appointment.
Health Canada is also reviewing updated booster shots for children six months and up.
No one-size-fits-all approach
At this point in Canada's vaccine rollout, there's a lot more nuance and less of a one-size-fits-all approach.
"Figuring out when people are supposed to get vaccines … it's getting more complicated," said Dr. Allison McGeer, an infectious diseases specialist at Sinai Health System in Toronto.
The days when Canadians of all ages lined up outside pop-up clinics to get a first or second dose — all to gain protection against a new virus their bodies had never encountered before — are long gone.
Since then, uptake for boosters has dwindled, while people are regularly being exposed to this virus at various times. Antibody-based protection after an exposure does fade as the months pass, meaning people may benefit from a booster at different points.
"There's different sets of circumstances that make it difficult to just give a blanket recommendation across the country," Tam noted.
McGeer said most people can safely wait six months or so between a previous vaccination or infection before getting another dose, which means the booster timing for each person can vary.
It's also worth holding out for the latest formulations, since "matching the vaccine as much as possible maximizes the immune response" against the virus' ever-evolving spike proteins, said Matthew Miller, an immunologist at McMaster University in Hamilton.
But there's another part of the fall push: Practicality. Vaccine rollouts, several experts stressed, are pricey and time-consuming, while uptake is often low. Only around four in 10 Canadians got flu shots during the last three seasons, for instance. Officials are now trying to streamline that process by offering both the influenza vaccine and COVID booster shots.
"And the goal is to try as hard as we can to be prepared for both of those vaccines rolling out at around the same time," Tam said.
Miller agreed most Canadians can consider a two-for-one approach: Getting a COVID booster and flu shot this fall during the same appointment.
"There's no inherent risk in doing that, and it increases convenience," he said. "For vaccines, like the flu shot that we have to update regularly, one of the biggest barriers to uptake of the vaccine is just the convenience factor."
Hospitals still 'stretched to the limit'
Medical experts are hopeful that vaccination coverage in the months ahead will help combat what could be another busy respiratory virus season.
"Our hospital capacity is so stretched to the limit that we need to do everything we can to reduce community rates of vaccine-preventable diseases like COVID, and influenza, and increasingly RSV, in order to ensure that things like routine surgeries and procedures and ER availability is there for all of the other things that people are dealing with," Miller said.
Kids may also have access to updated vaccines in the months ahead, officials say. In an email to CBC News, federal spokesperson Mark Johnson noted "some children are at increased risk of severe disease due to COVID-19 or developing post-COVID-19 condition, and vaccination is particularly important for these children."
Health Canada, he added, is actively reviewing submissions for updated vaccines for children six months of age and up.
Some people may benefit from more frequent shots
But what's most critical, several experts agreed, is for vulnerable populations to get the latest shots, perhaps even more frequently than the broader public.
People who are immunocompromised or pregnant, individuals with other pre-existing health conditions, and older adults all remain at a higher risk of serious illness from a COVID infection.
McGeer said for high-risk seniors such as long-term care residents, getting a booster in both the fall and spring will likely make sense. (Tam said Canada is planning ahead for the possibility of a broader spring vaccination campaign as well, if needed.)
A new analysis from a Yale University research team, published on Monday in the Journal of the National Cancer Institute, also suggests more regular shots should be considered for some cancer patients.
The majority of people undergoing cancer treatment could benefit from boosters every six months, the researchers found, with one key exception. Patients whose therapies directly impact their immune response likely need more frequent vaccinations to achieve the same level of protection, said Jeffrey Townsend, a professor of biostatistics at the Yale School of Public Health.
"It's becoming quite clear that for different individuals, there are different levels of risk, and that for different individuals, we need a flexible system that enables them to get boosters as they want," he said.