Will Canada have COVID booster shots this year? Probably, but not for everyone, experts say

Janet Langhad two doses of coronavirus vaccine, but she still double-masks every time she leaves her house.

That's because Lang, 73, takes oral chemotherapy to control a rare blood cancer. Although the drugs havehelped tokeep the cancer at bay,they also suppress her immune system, leaving her with the constant worry that although she's fully immunized, it's not enough to protect her against COVID-19.

"I'm feeling quite fragile," Lang told CBC News in an interview near her home in Waterloo, Ont.

A booster shot, she said, would help ease her fears, especially when it comes to the delta variant, she said.

"I'd like to see it put on the agenda [in Canada]," Lang said.

• CBC News connected with Janet Lang via COVID@cbc.ca. That's where we collect your stories, questions and tips about the pandemic.

Booster shots will be one of the next big decisions for Canadian officials, with the rise of the more transmissible delta variant, a lack of clarity over when boosters might be needed, and calls from the World Health Organization to get the planetvaccinated before rich countries worry about third doses.

In general, booster shots are used to increase the body's antibody response to a virus after the immune system has been "primed" by the initial vaccination (for example, tetanus shots). Additional vaccine doses can also help the body fight off differentvariants of a virus (likethe yearly flu shot).

Vaccine manufacturers, including Pfizer-BioNTechand Moderna, are working ondeveloping and testing the safety and efficacyof booster shots against Sars-CoV-2 the virus that causes COVID-19and potential new variants.

At this point, Canadian experts say, the existing COVID-19 vaccine schedule is offering excellent protection, including against the delta variant. But it's not yet known, they say,how long that protection lasts in various populations and therefore when or whether a booster shot will be needed.

Still, Lang may get her wish in the coming monthsif Canada follows the lead of the U.K.'s Joint Committee on Vaccination and Immunisation (JCVI), which is already issuing guidance on potentially starting a booster shot campaign in about two months.

"TheJCVI's interim advice is that, should a booster programme be required, a third COVID-19 vaccine dose should be offered to the most vulnerable first, starting from September 2021 to maximise individual protection and safeguard the NHS[National Health Service] ahead of winter," saidProf.Wei Shen Lim, COVID-19 chair forJCVI, in a news release.

The British committee recommends that those who are immunosuppressed, living in long-term care or retirement homes, people aged 70 years and older, and front-line health workers should be the first to get a third dose of COVID vaccine, or booster shot.

The U.K.'s targeted approach to booster shots is "spot on," said Dr. Allison McGeer,an infectious disease specialist at Mount Sinai Hospital in Toronto.

"People who live in long-term care facilities, people who are immunocompromised, do generate lower antibody levels and they decline faster over time," McGeer said.

"There are likely to be some of those people who will not be well-protected come October or November and who might be better protected if they get an extra dose of vaccine."

WATCH|COVID-19 vaccine booster being considered for the most vulnerable:

COVID-19 vaccine booster being considered for the most vulnerable

3 years ago

Duration 2:01

As more Canadians get vaccinated against COVID-19, now the discussion is turning toward a possible third dose. A booster shot, not necessarily for everyone, could potentially help control the spread of variants of concern, including delta.

Dr.AndrVeillette, an immunologist at the Montreal Clinical Research Institute and member of Canada's COVID-19 vaccine task force, said that although vaccines are doing an excellent job at controlling COVID-19 in Canada right now, he thinks it would be wiseto offerbooster shots to vulnerablepopulations in the fall.

"[In] light of the fact that we're probably going to get in Canada more and more of this delta variant, I think it's reasonable to start thinking that we're going to need also a booster or a third dose,"Veillette said.

Both McGeer and Veillette agree that booster shots should go to people in long-term care, those who are elderly and people with suppressed immune systems first.

WHO chief slams booster shots

But some experts, including the World Health Organization, say thatpolicymakers need to look at the broader picture when they're considering whether to offer booster shots including the fact that many people in the world have not yet been able to get even their first dose of a COVID vaccine.

"Some countries with high vaccination coverage are now planning to roll out booster shots in the coming months," said Dr.Tedros Adhanom Ghebreyesus, WHO's director general, in a news briefingon Wednesday.

"Vaccine nationalism, where a handful of nations have taken the lion's share, is morally indefensible and an ineffective public health strategy against a respiratory virus that is mutating quickly and becoming increasingly effective at moving from human-to-human," he said.

Some Canadian physicians, including Dr.Caroline Quach-Thanh, pediatric infectious disease specialist and medical microbiologist at Chu Ste. Justine in Montreal, share that concern and argue that one of the best ways to protect vulnerable people against COVID-19 is to vaccinate as many people as possible to build herd immunity.

"If you give those [third]doses here, it means that you're not giving themelsewhere, you know,worldwide. And at this point in time, what is absolutely needed is for the entire planet to be vaccinated, because if we want to stop the emergence of all those variants of concernthat we're seeing like day in, day out, we absolutely need to have everyone vaccinated,"Quach-Thanh said.

Both Veillette and McGeer, however, said that by the fall, everyone who wants to be vaccinated in Canada will likely have received their doses, and there should be plenty of supply to allow for boosters, especially if it's limited solely to those who are elderly and those who are immunocompromised.

Pfizer to seek FDA authorization for booster

On Thursday, Pfizer saidit plans to seekU.S. authorization for a third dose of itsCOVID-19 vaccine.

Dr.MikaelDolsten, Pfizer's chief scientific officer,told The Associated Press that early data from the company's booster study suggests people's antibody levels jump five- to 10-fold after a third dose, compared to their second dose months earlier.

In August, Pfizer plans to ask the U.S. Food and Drug Administration for emergency authorization of a third dose, he said.

But FDA authorization would be just a first step it wouldn't automatically mean Americans get offered boosters, cautioned Dr. WilliamSchaffner, a vaccine expert at Vanderbilt University MedicalCenter. Public health authorities would have to decide if they're really needed, he said, especially since millions of people still have no protection as they haven't been vaccinated.

NACIwatching to see if boosters needed

Canada'sNational Advisory Committee on Immunization (NACI) is watching the scientific data develop as they consider whether booster shots will be needed or when, said Anna Maddison, spokesperson for the Public Health Agency of Canada, in a statement emailed to CBC News.

"Based on previous evidence, booster vaccines may be required when immunity decreases below levels of protection and if there is an increase in breakthrough disease," Maddison said.

"Booster vaccines may also be required if the evolution of the virus, due to variants of concern, is no longer efficiently recognized by the natural immune system or the vaccine."

Even if all the data on boostersisn't in yet, Canada should be ready to use them as a proactive measure, Veillettesaid.

"I think the science may not be there [yet] to prove that elders need a third dose, but at the same time, do we need to go through what we went through before? Meaning, you know, outbreaks in elders' homes and then people getting very sick, people dying?"