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Will one dose do? Research suggests people recovered from COVID may need just one shot of vaccine

Last Updated Mar 25, 2021 at 7:28 am PDT

FILE - Dr. Joss Reimer, medical lead, Manitoba Vaccine Implementation Task Force draws a dose of the AstraZeneca COVID-19 vaccine at a clinic in Winnipeg, Friday, March 19, 2021. THE CANADIAN PRESS/John Woods
Summary

Expert says emerging data showing people who've recovered from COVID may only need one vaccine dose is promising

Quebec, France have already decided that just one COVID vaccine shot will do for those who have been infected

NACI currently reviewing data around the necessity of two doses for people who have had and recovered from COVID-19

VANCOUVER (NEWS 1130) – If you’ve recovered from COVID-19, there’s some promising research suggesting you may only need one dose of a two-shot vaccine.

That potentially has big implications for Canada’s COVID immunization program, which has gotten off to a slower start than hoped.

That research is being reviewed by the country’s expert vaccine panel. Scientists with the National Advisory Committee on Immunization (NACI) are looking at whether is a second dose is necessary for people previously infected with the virus.

Infectious diseases expert Dr. Isaac Bogoch says if the data holds, it makes sense not just from a medical and scientific standpoint, but from a public-health standpoint, too.

“There’s sadly a lot of people in Canada that have had COVID-19 that have recovered, and if they only require one shot of a COVID-19 vaccine, that really leaves potentially hundreds and hundreds of thousands of extra vaccine doses that can be used to vaccinate other people,” he explained.

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Emerging data from multiple groups suggests that a first shot of COVID-19 vaccines can basically act as a booster for people who’ve recovered from the virus and already have antibodies. Bogoch says the effect seems to be quite strong.

“If they receive just one shot of a two-shot vaccine series, they mount a very impressive immune response and this would likely be completely reasonable to protect them from COVID-19, when you compare it to, for example, someone who has not had COVID-19 and has received two doses of a vaccine,” he adds. “It really looks like this is a smart thing to do and, in fact, there are a few other jurisdictions that have done this already.”

Quebec and France have already decided that just one shot will do for those who have been infected.

When it comes to antibody testing, Bogoch notes there are difficulties with trying to implementing something like this on a national or provincial level.

“For starters, antibody testing is still far from perfect. There are, unfortunately, some false positives and there are some false negatives associated with it,” he explained. “In addition to that, it doesn’t entirely answer the question all of the time, and it’s cumbersome. It could potentially delay a vaccine rollout.”

He notes antibody testing would be a more practical option when someone clearly had evidence of a COVID-19 infection, along with a positive PCR test.

On Monday, B.C. Provincial Health Officer Dr. Bonnie Henry said that while “the jury is still out” on whether people who’ve recovered from COVID-19 could take one dose instead of two, she agreed emerging data is showing that this might be the case.

“I will say our National Advisory Committee on Immunization is looking at that question this week. They have the opportunity to look at data from many different parts of the world, and this is a question that many people have been asking, so we’ll have more advice from them,” she explained. “It is something we’ve been following closely. But it does look really great that many people who have been affected before have a really strong response to a single dose and may not be a booster.”