The co-chair of Canada’s COVID – 19 Immunity Task Force says she is now “very much in favor” of delaying the second dose of vaccines for shots that must be administered under a two-dose regimen.
The co- chair of Canada’s COVID – Immunity Task Force says she’s now “very much in favor” of delaying the second dose of COVID – 19 vaccines for shots that must be administered under a two-dose regimen.
It’s a relatively new reversal for Dr. Catherine Hankins, who told CBC Radio’s The House
- that she resisted the idea of extending the interval between first and second doses as recently as January.
- Listen to CBC Radio’s The House: Vaccination vexation
“I did not feel that we had the data,” Hankins told host Chris Hall. “But the population, real-world data coming in from the UK, from Israel and even from BC and Quebec are convincing to me.”
On Wednesday, Canada’s National Advisory Committee on Immunization (NACI) recommended that the maximum interval between the two doses should be stretched to four months to increase the number of people receiving their first shot.
The committee previously recommended that the maximum interval between Pfizer-BioNTech doses should be three weeks, a number that climbed to four weeks for the Moderna vaccine and weeks for the AstraZeneca-Oxford product. The newly approved Johnson & Johnson shot is a single-dose vaccine.
The updated guidance comes from findings from two clinical trials examining the efficacy of the Pfizer and Moderna vaccines after a single dose, as well as population health data from several countries – and two Canadian provinces – on how well those shots performed after being administered once.
While the population studies yielded lower efficacy results after one dose than the clinical trials, NACI said the difference was expected given that vaccine effectiveness tends to be lower in the general population than it is under the controlled setting of a clinical trial.
CBC News: The House
Vaccination frenzy grips Canada
CBC’s JP Tasker walks through a busy week of vaccine developments and COVID – Immunity Task Force co -chair Dr. Catherine Hankins discusses prospects for achieving mass immunization.
One dose still confers benefits – and reduces transmission
Hankins said it was the population health data that convinced her to change course.
“Basically, it’s showing that you have sustained protection … for two months, in terms of reducing hospitalizations and deaths, including against this B 117 variant that was first identified in the UK, “she said.
” So you have those benefits to the individuals that get the single dose, but you have then this additional benefit that they showed in Israel, that people who get infected after they’ve had the vaccine … are much less likely to transmit to other people. “
Hankins, who is also a professor of public and population health at McGill University in Montreal, cautione d that the new recommendation does not mean people should forgo the second dose altogether.
“What’s clear is we can offer more individuals the direct benefit that single dose will bring, plus the indirect benefit of reduced transmission that will avert hospitalizations and deaths for people who do not yet have the vaccine. So to me, it’s a win-win situation. “
Before NACI released its guidelines, British Columbia had already moved to implement a four-month gap in administering doses. A number of other provinces have now extended their dose intervals to widen initial rollout efforts.