People infected with COVID-19 may need just one dose of vaccine, studies say (courtesy: The Toronto Sun)

by Seva Lamberdar Thu May 27, 2021 11:29 am

VANCOUVER, Canada (May 25, 2021) — Scientists at the National Advisory Committee on Immunization are reviewing research that suggests people who have been infected with COVID-19 can turbocharge their antibodies with just one dose of a vaccine.

The committee is “actively reviewing evidence on the protection offered by one dose for those previously infected, and whether a second dose continues to be necessary,” says a statement from the panel.

Caroline Quach-Thanh said the committee is “debating” the question of how many vaccine doses someone who has been infected with COVID-19 requires.

“France and Quebec have said only one,” said Quach-Thanh, chair of the committee, in an email.

Quebec’s Health Department confirmed Thursday that previously infected patients will only require a single dose of vaccine, a decision made by experts at the province’s public health institute and the province’s immunization committee.

They said those with a confirmed infection have built up an immune memory during infection, so a single dose of vaccine acts as the booster.

Authorities added that Quebecers previously infected will be able to secure a second dose if they want one, and anyone immunosuppressed who has been infected should get both doses.

Studies have suggested people who have had COVID-19 may produce the required antibody response with just one dose of a vaccine.

A letter in the New England Journal of Medicine earlier this month says the question of whether one dose is enough “requires investigation.” It’s written by 32 researchers from the Icahn School of Medicine at Mount Sinai in New York after conducting a small study.

It suggests people who have been infected with the novel coronavirus may produce 10 to 45 times as many antibodies after the first dose of the Pfizer-BioNTech or Moderna vaccines compared with someone who hasn’t had COVID-19. The research is yet to be peer reviewed.

Quach-Thanh said data shows that the response to the first dose of vaccine is strong for those who have been infected with the virus.

“Like a booster dose,” she said.

Those who have been infected and get a second shot may also have stronger side-effects, such as fever, aches and feeling tired, which are signs their immune system is already primed, Quach-Thanh said.

“The question that remains is: is that true for everyone or at least for the vast majority?”

Dr. Bonnie Henry, British Columbia’s provincial health officer, said early data from around the world suggest people who have had a lab-confirmed positive test for COVID-19 get a good response from just one dose of a vaccine.

“The jury is still out but more and more it is looking like they get a really strong booster effect from a single dose and a second booster may not be necessary,” she said.

https://torontosun.com/news/national/people-infected-with-covid-19-may-need-just-one-dose-of-vaccine-studies-say