Health-care workers wait in line at a UHN COVID-19 vaccine clinic in Toronto on Thursday, January 7, 2021. THE CANADIAN PRESS/Nathan Denette

Health-care workers wait in line at a UHN COVID-19 vaccine clinic in Toronto on Thursday, January 7, 2021. THE CANADIAN PRESS/Nathan Denette

Canadians who have had COVID-19 should still get the vaccine, experts say

Pfizer-BioNTech and Moderna vaccines were found to have a 95 per cent efficacy

Studies have suggested previous COVID-19 infections may result in promising levels of immunity to the virus, leading to questions of whether those who’ve already recovered from the disease still need a vaccine.

And is there urgency to inoculate them, or can they move to the back of the vaccination line?

Experts say a vaccine will likely offer the safest bet for longer-term protection, meaning those with previous infections should still get them. And prior COVID illness shouldn’t determine someone’s place in the queue.

The exact level of immunity acquired from a natural infection is yet to be fully determined, says Dr. Andre Veillette, a professor of medicine at McGill who’s also on Canada’s COVID-19 vaccine task force.

It may be that protection begins to wane quicker in some people, or that those with previous mild infections aren’t as protected as someone who had more severe symptoms, he says. Still others may think they’ve had a COVID-19 infection but can’t be sure if they didn’t get tested at the time.

“I would say the simple rule would be that we vaccinate people who’ve had prior infections, just like everybody else,” Veillette said. “If you had the infection, yes, you may have some protection, but it may not last a long time, and it may not be as good as the vaccine.”

Pfizer-BioNTech and Moderna vaccines were found to have a 95 per cent efficacy in clinical trials in protecting against severe disease.

But there are still questions around whether the vaccines can actually prevent someone from catching the virus and spreading it to others. While Moderna has some data that their product may protect against acquiring the virus, it’s still unclear.

Antibodies from natural infections suggest the same — that they may protect us from getting really sick again, but not from getting the virus a second time.

While there have been some cases of reinfection around the world, immunology expert Steven Kerfoot says the fact we’re not seeing more of those suggests the immune response from initial COVID-19 infections is probably “pretty strong.”

Kerfoot, an associate professor at Western University, says vaccines are designed in a way that should produce an immune response “at least as good or better” than what we get after a natural infection.

“So it may help fill in holes where people may not have developed an immune response effectively to the virus,” Kerfoot said. “If anything, the vaccine could as act as its own booster that would improve your immunity.”

READ MORE: B.C. adjusts COVID-19 vaccine rollout for delivery slowdown

While some studies have suggested antibodies may disappear relatively quickly after COVID-19 infections, others have found a more lingering immune response. An American study published this month showed antibodies present for at least eight months, and possibly longer.

Even studies suggesting an early drop-off of antibody levels aren’t concerning, Kerfoot says. Infections trigger the body to produce other immune cells and memory cells that reduce slowly over years and help fight off future invasions from the same virus.

If the immune response in those with past COVID infection is expected to be lengthy, could there be justification to defer their inoculations, especially if vaccine supply is low?

It will be up to provinces to decide priority in each stage of their rollouts, but Jason Kindrachuk, a virologist with the University of Manitoba, says that will be a tricky decision.

“I don’t think we can use prior infection as an indicator of priority, because we just don’t know what that person’s immune response actually is,” Kindrachuk said. “We don’t know what long-term immunity looks like in those folks.

“The recommendations are going to be that everybody gets vaccinated because that way we know — across vulnerable groups and all ages and different demographics — they’ll all get a robust immune response.”

Veillette adds that many people with previous COVID cases were also in higher-risk settings — either because of their jobs or living environments — that would theoretically put them at risk for reinfection.

And if they were to get the virus again but not show symptoms, they could still pass it on to other people.

“There’s probably a whole spectrum of situations there, and when there’s so many variables it’s better to have a simple rule,” he said. “So I think that’s another reason to vaccinate previously infected people.”

Melissa Couto Zuber, The Canadian Press


Like us on Facebook and follow us on Twitter.

Want to support local journalism during the pandemic? Make a donation here.

Coronavirusvaccines

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

A beautiful sunny afternoon showcasing Mount Cain in all its glory. (Kimberley Kufaas Photography)
Mount Cain to start construction on new lodge once season ends

The North Island ski hill has been awarded $874,000 to build a brand new lodge.

The U’mista Cultural Society is getting $294,000 in funding. (North Island Gazette file photo)
North Island gets infrastructure and jobs boost from Economic Recovery Plan

“I’m thrilled that so many North Island organizations are benefiting from this funding”

Gordie Wigman and Edward Cote won $55,425.85 from the draw on Dec. 28. (BCLC photo)
Port McNeill friends win over 55 grand

Wigman and Cote purchased the ticket from the Port McNeill Petro Canada on Mine Road.

OrcaFest parade 2019. (North Island Gazette file photo)
COVID-19: Port McNeill’s annual OrcaFest cancelled again

“We promise you that once we are safely able to do so, OrcaFest will be back!!”

FILE – A COVID-19 vaccine being prepared. (Olivia Sullivan/Sound Publishing)
B.C. seniors 80 years and older to get COVID vaccine details over next 2 weeks: Henry

Province is expanding vaccine workforce as officials ramp up age-based rollout

Abbotsford’s Kris Collins turned to TikTok out of boredom when the provincial COVID-19 lockdown began in March 2020. She now has over 23 million followers on the video app. Photo: Submitted
Internet famous: Abbotsford’s Kris Collins is a TikTok comedy queen

Collins has found surprise stardom alone with a phone

A Vancouver restaurant owner was found guilty of violating B.C.’s Human Rights Code by discriminating against customers on the basis of their race. (Pixabay)
Vancouver restaurant owner ordered to pay $4,000 to customers after racist remark

Referring to patrons as ‘you Arabs’ constitutes discrimination under B.C.’s Human Rights Code, ruling deems

BC Ferries experienced heavy traffic on Feb. 27 following cancellations the day before due to strong winds and adverse weather. (Black Press Media file photo)
BC Ferries sailings fill up quickly after Friday cancellations due to high winds

Waits expected on Swartz Bay-Tsawwassen route, Horseshoe Bay-Departure Bay route

1957 photo shows Six Mile House-sponsored #4 1932 Ford stock car with Frank Morris (from left), Ted Mackenzie, Bill Sim and driver Gerry Sylvester. (Bud Glover/Victoria Auto Racing Hall of Fame)
Memories race as Western Speedway approaches its finish line

‘It was life to us:’ Vancouver Island racers, crew will never forget what the track gave them

Nanaimo children’s author and illustrator Lindsay Ford’s latest book is ‘Science Girl.’ (Photo courtesy Lindsay Ford)
B.C. children’s writer encourages girls to pursue the sciences in new book

Lindsay Ford is holding a virtual launch for latest book, ‘Science Girl’

Pig races at the 145th annual Chilliwack Fair on Aug. 12, 2017. Monday, March 1, 2021 is Pig Day. (Jenna Hauck/ Chilliwack Progress file)
Unofficial holidays: Here’s what people are celebrating for the week of Feb. 28 to March 6

Pig Day, Canadian Bacon Day and Grammar Day are all coming up this week

Staff from the Marine Mammal Rescue Centre, passersby, RCMP and Nanaimo Fire Rescue carried a sick 300-kilogram steller sea lion up the steep bluff at Invermere Beach in north Nanaimo in an attempt to save the animal’s life Thursday. (Photo courtesy Marine Mammal Rescue Centre)
300-kilogram sea lion muscled up from B.C. beach in rescue attempt

Animal dies despite efforts of Nanaimo marine mammal rescue team, emergency personnel and bystanders

Doctors and counsellors warn of an increase in panic attacks, anxiety, depression and suicide ideas between ages 10 to 14, in Campbell River. ( Black Press file photo)
Extended pandemic feeding the anxieties of B.C.’s youth

Parents not sure what to do, urged to reach out for help

Kara Sorensen, diagnosed with lung cancer in July, says it’s important for people to view her as healthy and vibrant, rather than sick. (Photo courtesy of Karen Sorensen)
B.C. woman must seek treatment overseas for inoperable lung cancer

Fundraising page launched on Karen Sorensen’s behalf, with a goal of $250,000

Most Read