Will Canada approve a first-dose-first strategy?
This week, buoyed by the apparent success of a “first dose first” vaccine rollout, U.K. Prime Minister Boris Johnson unveiled a plan to slowly unshackle England from COVID restrictions by the end of June.
The U.K.’s controversial strategy to space vaccine doses up to three months apart, rather than the originally approved three to four weeks, in order to give as many people at least one shot sooner could see every British adult offered a first dose of a COVID vaccine by the end of July — months sooner than Canada.
Now, an independent federal expert advisory panel is once again mulling dosing gaps in Canada: How far can you push it to give more people shots?
“We are already at six weeks,” Dr. Caroline Quach, chair of the National Advisory Committee on Immunization, said in a brief email exchange with Postmedia News before two days of meetings this week. “(The panel) will see what else can be recommended.”
It’s unlikely the group would endorse the U.K. plan of a 12-week interlude between doses. Some observers think they won’t blink at nine weeks but that it’s not clear where they will stop.
The panel’s deliberations come as a third vaccine — this one from Oxford University and pharma giant AstraZeneca — was officially authorized for use in Canada Friday. Canada’s pre-ordered, 20 million doses are scheduled to arrive in the second and third quarter of the year.
Except for the Johnson and Johnson vaccine, which is a single-shot jab, a second booster dose is vital to lock in and extend immunity for all the COVID vaccines. On this, everyone agrees. No one is saying one-dose-and-done.
But the debate over delaying those second, booster doses has been polarizing and emotional, with opponents warning it’s not known how long immunity persists after the first dose and that “sub optimal” vaccination risks giving rise to more superinfectious, mutated variants.
Others argue immunity doesn’t wane that fast between shots and let’s not leave people unprotected and risk more deaths and economic casualties.
While the data are still early, “the indications are that there’s a good level of protection after just one dose,” Canada’s deputy chief public health officer, Dr. Howard Njoo, told reporters last week.
Ottawa has said it expects to receive a combined 29 million doses of the Pfizer and Moderna vaccines by the end of June, enough to fully vaccinate 14.5 million people. But immunizing 20 million people — if logistical and technical glitches can be overcome — by spreading out the shots could help break the back of the epidemic sooner. The vaccines currently aren’t approved for children under 16.
“It’s clearly advantageous if we can get most of the population vaccinated” with a first shot by early summer, said Aidan Hollis, a professor of economics at the University of Calgary who specializes in pharmaceutical markets.
“The U.K. has been stretching out the timing of doses for quite a while now,” he said, stressing he’s not trying to claim expertise in immunology or vaccinology. “There’s an opportunity to learn from what’s happening in other jurisdictions.”
The original dosing schedules for Canada’s two approved vaccines — PfizerBioNTech and Moderna — require two doses, 21 days (Pfizer) and 28 days (Moderna) apart.
In January, amidst a lethargic vaccine rollout, Quach’s expert vaccine advisory panel came up with a compromise: It said that spacing shots out to a maximum of six weeks seemed safe and reasonable, though the original schedule was still preferred.
“In our usual Canadian fashion, provinces responded in different ways,” said Dr. David Naylor, co-chair of the federal government’s COVID-19 Immunity Task Force. Ontario opted for 42 days. Quebec allowed 90 days between jabs — a scheme that appears to be working.
According to preliminary, unpublished data, the PfizerBioNTech and Moderna vaccines have been roughly 80 per cent effective in preventing disease after the first dose, Quebec public health officials said this week.