Will a COVID booster protect me from the new COVID variant? What to know as doctors warn of a summer surge

As summer approaches, experts are warning at-risk Canadians not to ignore the latest variant of COVID-19.

Earlier this week, Ottawa's Deputy Medical Officer Dr. Trevor Arnason reminded the public that there's a pattern of COVID cases increasing in the summer months — especially for seniors and people who are immunocompromised.

“It is hard to overstate how much the older adult population is affected differently by COVID-19,” Arnason told The Ottawa Citizen.

Approximately 70 per cent of the city's senior population have not received a COVID-19 vaccine within the past 6 months.

"We are still seeing lots of older adults who end up in hospital, and there are still deaths," Arnason explained.

The situation in Ottawa is not unique. In an interview with Yahoo Canada, Dr. Donald Vinh, an infectious disease specialist at McGill University said the new group of COVID subvariants pose potential risks for seniors and vulnerable groups.

What are the FLiRT variants of COVID?

The "FLiRT" variants, KP.1, KP.2, and KP.3, are derived from the JN.1 Omicron subvariant that was dominant during 2023 and winter 2024, and are quickly beginning to dominate cases. Although they're closely related to one another, Vinh said the mutations of the FLiRT variants "allow them to capitalize on weaknesses in the immune system" and cause infections. Vinh explained that the new subvariant can cause respiratory tract infections with symptoms that vary in severity.

"For some people that can look like a cold where they have a runny nose, sniffles or sore throat. But for some people they can be quite sick — they can have fevers, feel like they’ve been run over by a truck and feel achey," he said. "Some people even have either trouble breathing or it exacerbates an underlying medical condition like chronic lung disease or heart disease."

Am I protected from FLiRT subvariants if I recently had COVID?

Because the FLiRT subvariants are new and closely related to JN.1, anyone who has had COVID in 2024 (particularly the JN.1 strain) or recently received a booster may be at an advantage against the new COVID variants. However, Vinh said anyone whose last COVID infection was in the fall of 2023 or hasn't received the updated XBB.1.5 vaccine formulation might not be as armed against the emerging strains.

Will a COVID booster protect me from the new substrains?

The latest vaccine formulation was released in the fall of 2023, and the next formulation is currently under development. Although the available boosters aren't exactly tailored to the new emerging strains, Vinh said they will "provide some level of protection."

"We have to remember that the current variants are descendants from the XBB.1.5 Omicron subvariant," he explained. "[With the latest vaccine] you might not be able to target the great-grandchild, but you can still target the parent."

According to Vinh, the latest vaccine formulations are expected to be released in fall 2024. Even though it might only be a few months until a new booster is available, it's imperative for at-risk groups to arm themselves as much as possible heading into summer.

“We’re really talking about the people who are most at risk in the elderly age category, people who are immunocompromised but not necessarily in the oder age group,” he said. “Should they get [COVID] it may be a flu-like disease but it could progress to a life-threatening disease."

Vinh said he would "strongly" encourage people over 65, who are immunocompromised from cancer treatments, have chronic heart or lung disease to get a COVID booster.

"It will provide some protection," he said. "'Some protection' isn't great protection — but it's better than nothing."

If your last vaccine was in 2023, Vinh there is "minimal" risk to receiving a booster ahead of summer.

"It's more of a social inconvenience than a medical one," he said.

Will the current rapid testing detect the new COVID subvariants?

One of the issues with the emerging strains of COVID is detection. Healthcare settings using polymearse chain reaction (PCR) tests are more accurate at identifying the new strains of COVID. However, the rapid antigen tests are different. Vinh says its possible that some of the rapid tests that were manufactured years ago might not be able to detect the latest strains of COVID.

"It's possible that a person could pick up a rapid test, do it properly, and the test— which isn't expired— comes back negative," he said. "There are other reasons why the test could be negative, but it's a little bit hit and miss."

These negative tests could potentially transmit the virus to someone at-risk. Wearing masks when you don't feel well around vulnerable persons and practicing social distances are encouraged.

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