Boosters recommended for those over 50, younger people may also get 3rd shot: NACI

OTTAWA -

The National Advisory Committee on Immunization is now strongly recommending adults over the age of 50 be offered COVID-19 boosters, while those aged 18 to 49 “may” be offered boosters based on individual risks and where they live.

In its latest update to its booster shot recommendations released on Friday, NACI is also reiterating its previous recommendations to prioritize boosters for:

• those living in long-term care homes;
• those who received two doses of the AstraZeneca vaccine or one dose of the Janssen vaccine;
• certain immunocompromised individuals;
• adults in First Nations, Inuit and Métis communities; and
• front-line health-care workers who have direct close physical contact with patients.

NACI continues to align with Health Canada’s authorization that either the Pfizer-BioNTech and Moderna mRNA vaccines can be offered as boosters for anyone 18 and older, at least six months after the primary vaccine course.

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However, citing evidence of lower reported rates of myocarditis or pericarditis following the Pfizer vaccine, NACI is suggesting it is the preferred vaccine to administer as a booster to those ages 18 to 29.

Generally speaking, the groups that NACI is now strongly recommending be offered boosters were among the first to be prioritized for initial vaccine doses, meaning they are closer to it being six months after their second dose than the younger age groups.

NACI is suggesting these considerations be weighed in determining the need for a booster dose: the local epidemiology, regional health system capacity and access, and rate of vaccine update in the population.

As well, Canadians should consider whether they are at risk for severe illness from COVID-19, are at increased risk for waning protection, or are at high risk of transmission to others in deciding whether to receive a booster dose.

“NACI recommends, and health authorities in Canada agree, that immunization in those who are eligible, but have yet to receive the primary series should continue to remain the top priority in Canada,” said Chief Public Health Officer Dr. Theresa Tam, announcing NACI’s latest findings during a press conference on Friday.

“Modelling results suggest that booster doses are projected to reduce infections and severe illness in the population, at least over the short-term,” reads NACI’s report.

• COVID-19 vaccine booster eligibility by province and territory in Canada

As has been the case throughout the pandemic, provinces and territories are responsible for deciding their vaccine rollout eligibility strategies and whether or not to follow NACI’s recommendations.

UPDATE COMES AMID OMICRON FEARS

This updated advice comes after the federal government requested on Tuesday that NACI “quickly” review its guidance on prioritizing COVID-19 booster shots in light of concerns over the Omicron variant.

Asked why he sought this update when most provinces have already been deciding who to prioritize for boosters, Health Minister Jean-Yves Duclos said Friday that it was because “there is a significant level of variability,” across the country.

“There is no intention of imposing a one-fit-for-all set of measures when it comes to boosters across Canada, but I think there is a need, and I would say even a responsibility for NACI at the federal level to help provinces come closer together,” he said.

Health officials have expressed concerns that the Omicron may be more vaccine-resistant, because it is highly mutated. However, it remains unclear just how transmissible and severe infection by the variant B.1.1.529 might be.

“Now and during the winter months, while the virus continues to circulate worldwide, and the significance and impact of the Omicron variant of concern is being assessed, the need for heightened vigilance remains,” Tam said.

NACI said that while Omicron’s emergence was considered in updating this guidance, the immunization experts also factored in the recent increase in COVID-19 cases, and further evidence of the potential benefit and safety of booster doses.

“NACI acknowledges that the epidemiology of COVID-19… and the evidence on booster doses of COVID19 vaccines are rapidly evolving, and continues to monitor the evidence,” reads the latest report.

Asked what her advice would be to people who are now considering waiting to get a booster in case a potentially new vaccine formulation targeting Omicron is developed, Tam said should that be the case, it could be several months before another vaccine is available.

“The Omicron variant-specific vaccines are going to take months, but right now we have the potential for a Delta surge,” she said.

WILL THIRD SHOTS BECOME MANDATORY?

With NACI now recommending, either strongly or in a discretionary manner, third doses of the mRNA Pfizer or Moderna vaccines for all adults, questions were raised Friday over whether the current two-dose vaccine series could be expanded to require three doses to be considered fully vaccinated.

In its report, NACI states that while they are currently describing these third doses as boosters—intended to stimulate the immune response once protection has waned—they continue to monitor whether third shots should be considered part of the primary series to establish a stronger immune response.

“NACI will adjust the terminology as required,” reads the latest guidance.

In an interview on CTV News Channel on Friday ahead of NACI’s update, Dr. Peter Juni, the scientific director of Ontario's COVID-19 Science Advisory Table, suggested that Canada shouldn’t be calling these third doses “boosters” any more.

“For many of the age groups it will just be the third dose that will be needed,” he said.

Speaking to whether third doses could become required, Tam said that will become clearer as more time passes and the long-term efficacy of the current COVID-19 vaccines becomes better understood.

“This is an evolving story… Historically in other vaccine programs I think it's worth noting, like for hepatitis or human papilloma virus, that the original authorized schedules did evolve over time, over years, as we learn more… and we learn how to refine and optimize the schedule within the series,” said NACI’s executive secretary Dr. Matthew Tunis during the press conference. “That's a fairly normal progression within vaccine programs. You start with what's available when the products are first authorized and the clinical trials are conducted, and then over time, we iterate, study and evolve.”

DOES CANADA HAVE BOOSTER SUPPLY?

Earlier this week, Prime Minister Justin Trudeau said that should the call come to expand COVID-19 booster shot access, the supply will be there.

“I can assure you that our country has access to more than enough vaccine doses for all eligible Canadians,” Procurement Minister Filomena Tassi said on Friday, following NACI’s update.

“Thanks to our strong procurement strategy, we will be able to quickly deploy those booster shots and provide an additional degree of protection for Canadians,” said Duclos.

Part of the calculus with Canada’s booster supply plays into the ongoing questions over whether or not Canada should be offering third doses to healthy adults rather than prioritizing sending doses to other less-vaccinated nations to potentially help prevent further mutations of the virus.

“We can’t eat the cake and have it too. Either we now just take these vaccine doses we have in our freezers out and send them to low and middle income countries, or we use them here. It doesn’t make sense to play safe and keep them in the freezer,” said Juni.

“So either we protect our population… if they now start to see we really have a challenge with Omicron, or we just say ‘OK, we’re ready to gamble’ and then we give these third doses away. The point really is it doesn’t help anybody if they stay in the freezer, and that’s one of the discussions we should have,” said Juni.

Through global vaccine-sharing initiative COVAX, Canada has promised to donate 200 million doses by the end of 2022, though so far approximately 8.3 million doses have been donated.

Ministers are expected to have more to say about the federal COVID-19 response and Canada’s vaccine procurement and delivery schedules in a 1 p.m. EST press conference.

With files from CTV News’ Sarah Turnbull