B.C.’s Provincial Health Officer, Dr. Bonnie Henry, made a cautious reference at her briefing Tuesday to a return to somewhat normal by this summer. Theatre and sports, visits with friends, a glimmer of anticipation for warmer times in warmer weather.
Her optimism is a result of a bold decision by her office, announced Monday, to extend the interval between the first shot of vaccine and the second to four months – 120 days, up from the manufacturers’ recommendation of 21 to 28 days. No other province has a delay of that length. Quebec increased its gap between first and second shot to 90 days in January, a controversial move at that time.
By the end of Monday, B.C.’s decision was facing stiff criticism from Canada’s chief science adviser, who called it a “population-level experiment.” In a later interview with The Globe, Dr. Mona Nemer challenged Dr. Henry to explain how she concluded that the gap is safe.
“I’m not aware of data that that would support a four-month delay,” Dr. Nemer said. “I think it would be really important to be transparent about the data that is forming the basis of the decision [and] to be transparent about what we don’t know.”
In response, Dr. Henry referred, among other research, to work by the B.C. Centre for Disease Control, published in the New England Journal of Medicine, which notes data from Quebec, Israel and Scotland are behind a growing consensus that the first shot provides protection of 80 per cent or better, and that recipients can safely wait for a booster without losing benefit.
British Columbia’s decision to delay for four months is expected to get important validation as early as this week from an expert panel that advises the federal government on vaccination. The National Advisory Committee on Immunization has determined that second doses can be delayed for up to four months to immunize a greater number of people with one dose.
The shift, confirmed by two sources familiar with the deliberations, will open the door for other provinces to follow B.C.’s lead.
In Alberta, Health Minister Tyler Shandro said Tuesday “fantastic evidence” out of places such as Britain and Quebec show the effectiveness of the vaccines after just a single dose. He said he expects to make an announcement soon, though the province hasn’t yet decided just how long to delay second doses.
“It’s going to give us an opportunity to get more people vaccinated more quickly,” Mr. Shandro said during a news conference on Tuesday.
Ontario Health Minister Christine Elliott on Tuesday said her province was waiting on published guidance from NACI about extending interval doses for vaccines. “This would be a considerable change of course, if you can extend the vaccines for four months. That makes a huge difference. You have more people be vaccinated, at least with the first dose, and with the variants of concern out there this could make a significant difference for Ontario in reducing hospitalizations and deaths,” Ms. Elliott said.
A new research paper produced by Saskatchewan Health Authority concludes that delaying the second shot by up to 24 weeks “shows progressive benefit to population immunity.” The modelling suggests that Saskatchewan could reach herd immunity four weeks faster with the implementation of a 12-week spacing regimen, or 10 weeks faster, if the booster was delayed by 24 weeks.
Michael Houghton, a Nobel laureate and vaccine researcher at University of Alberta, said evidence is already available that the AstraZeneca vaccine provides good protection at three months between doses, though he added that a four-month delay is “more of a calculated gamble.”
The new target means that B.C. has fast-tracked its vaccine schedule for 70,000 people, and now expects all eligible adults will have the opportunity to get the first dose of a COVID-19 vaccine by the end of July, two months earlier than it had originally planned.
“We know that maximizing the benefit of a single dose for more people in British Columbia is going to get us to our post-pandemic goal,” Dr. Henry said Tuesday, “and is going to protect more people, keep more people from needing hospitalizations and prevent more people from dying.”
This is the weekly Western Canada newsletter written by B.C. Editor Wendy Cox and Alberta Bureau Chief James Keller. If you’re reading this on the web, or it was forwarded to you from someone else, you can sign up for it and all Globe newsletters here. This is a new project and we’ll be experimenting as we go, so let us know what you think.