Dr. Bonnie Henry talks about phase two in B.C.’s COVID-19 immunization plan as Premier John Horgan and Minister Arian Dix look on during a press conference at Legislature in Victoria, B.C., on Monday, March 1, 2021. THE CANADIAN PRESS/Chad Hipolito

Dr. Bonnie Henry talks about phase two in B.C.’s COVID-19 immunization plan as Premier John Horgan and Minister Arian Dix look on during a press conference at Legislature in Victoria, B.C., on Monday, March 1, 2021. THE CANADIAN PRESS/Chad Hipolito

Vaccines: B.C. pushes ahead with delayed second doses as Ontario waits for national guidance

Dr. Bonnie Henry said she expects the national immunization committee to align with the province’s decision

Ontario is waiting for a recommendation from the National Advisory Committee on Immunization before delaying second doses of COVID-19 vaccines, while British Columbia is pushing ahead with its plan to extend the interval to four months.

A researcher whose work underpinned B.C.’s decision said Tuesday that the change was based on strong data. Dr. Danuta Skowronski, epidemiology lead of influenza and emerging respiratory pathogens at the B.C. Centre for Disease Control, said Pfizer-BioNTech underestimated the efficacy of the first dose of its own vaccine in its submissions to the U.S. Food and Drug Administration.

Skowronski said the company included data from the first two weeks after trial participants received the shot, which is a time when vaccines typically aren’t effective. When she and her colleagues adjusted the data, they made a surprising discovery.

“We took that into account and showed that the vaccine efficacy was not 52 per cent, it was actually 92 per cent. That was actually very similar, that first-dose efficacy, to what the other manufacturer, Moderna, had actually itself correctly analyzed in its own submissions to the FDA,” she said in an interview.

Skowronski said the four-month interval is based on the basic principles of vaccine science. The protection from a first dose of vaccine does not suddenly disappear, it gradually wanes over time, and scientists are typically more concerned about providing a second dose too soon rather than too late, she said.

“I think if the public had a chance to hear and to understand that, they would say, ‘OK, this is not messing around. This is really managing risk in a way that maximizes protection to as many Canadians as possible.’”

She said the province’s decision was backed up by data from Quebec, the United Kingdom and Israel, and comes at a time when B.C. residents are experiencing severe social and economic effects from isolation during the pandemic.

Skowronski added that the B.C. Centre for Disease Control also examined the effects of a single dose on long-term care residents and health-care workers in the province and found that it reduced the risk of the virus by 80 per cent within two to three weeks.

Provincial health officer Dr. Bonnie Henry has said she expects a statement from the national immunization committee aligning with the province’s decision, while Ontario Health Minister Christine Elliott said Tuesday she wanted to wait for such a recommendation.

She said extending the interval between doses would allow the province to get some level of protection to more people.

“This would be a considerable change,” she said.

“With the variants of concern out there, this could make a significant difference for Ontario in reducing hospitalizations and deaths. So, we are anxiously awaiting NACI’s review of this to determine what they have to say in their recommendations.”

Dr. Shelley Deeks, vice-chair of the national committee, said in an email the group is expected to issue a statement on extending the dose interval on Wednesday, but she did not confirm it would align with B.C.’s plan.

Alberto Martin, a University of Toronto immunology professor, said his understanding of a published Pfizer-BioNTech clinical trial was that the first dose provided 60 per cent protection and the second dose provided 95 per cent protection.

He said there is “obviously some concern” about B.C.’s plan because he is not aware of any clinical trial that examined a four-month gap between doses.

“There might be a risk that you’re not going to achieve that 95 per cent protection that the Pfizer-BioNTech vaccine can achieve with two doses separated by a few weeks apart,” he said.

However, he said difficult times — when the vaccine supply is so limited — require drastic measures.

“I think what they’re trying to do is immunize as many people as possible, get partial protection in the population and then hope for the best that the second dose that comes in four months later will boost the immune response enough to achieve that 95 per cent protection,” he said.

“It’s a difficult decision to make. I don’t know whether I’d like to be in that position, but I think it’s understandable why they’re doing this.”

Coronavirus

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

B.C. Cattlemen’s Association general manager Kevin Boon. (B.C. Cattlemen’s Association photo)
COVID, BSE, water access and private land rights: B.C. Cattlemen’s general manager weighs in

Kevin Boon said positive aspect of pandemic is more people interested in where their food comes from

B.C's COVID-19 dashboard shows the peaks and valleys of cases prior to the record daily report of 132 on April 9, 2021. (Dashboard image)
Interior Health has record day of COVID-19 cases

132 cases reported Friday, April 9, more deaths in Vernon hospital outbreak

The BC Wildfire Service will be partnering with Simpcw First Nation this month in the implementation of a prescribed burn next to their community of Chu Chua. The controlled burn will be highly visible to Highway 5 and all communities in the immediate area. Pictured is a prescribed burn that took place on the Kanaka Bar Reserve last month in partnership with the Kanaka Bar Band and BC Wildfire Service. (BC Wildfire Service Facebook photo)
Simpcw and BC Wildfire Service to hold controlled burn near Barriere

Burn will be highly visible to Chu Chua, Barriere, Darfield, Chinook Cove, Little Fort and Highway 5

District of Clearwater meetings are open to the public. The meeting agendas and past meetings minutes can be viewed on the DOC's website. Every meeting has time allocated at the end for comments from the public.
Clearwater to benefit from funding through Ministry of Tourism initiative

The District’s Trails Task Force was sucessful in securing a grant for $684,000.

Carlos Sigurnjak went missing about 4 p.m. on Tuesday, April 6, according to a Facebook post by his family. (Facebook/Carlos Sigurnjak profile)
UPDATE: Clearwater RCMP find missing man from Kelowna

Sigurnjak was found just before 2 p.m. April 8 by a passerby.

Burnaby MLA Raj Chouhan presides as Speaker of the B.C. legislature, which opened it spring session April 12 with a speech from the throne. THE CANADIAN PRESS
B.C. NDP promises more health care spending, business support in 2021 budget

John Horgan government to ‘carefully return to balanced budgets’

A lady wears a sticker given out after receiving a COVID-19 vaccine at a clinic in Richmond, B.C., Saturday, April 10, 2021. THE CANADIAN PRESS
B.C.’s COVID-19 case count slows after last week’s peak

3,219 new cases since Friday, 18 additional deaths

North Cowichan councillor Tek Manhas did not violate the municipality’s code of conduct by posting a sexist meme on Facebook, council concludes. (File photo)
B.C. municipality to take no action against councillor who posted sexist meme

Tek Manhas’s meme doesn’t violate North Cowichan council’s code of conduct, municipality concludes

—Image: contributed
Indoor wine tastings still allowed in B.C., not considered a ‘social gathering’

“Tasting is really just part of the retail experience. The analogy I use is you wouldn’t buy a pair of pants without trying them on.”

A sign on a shop window indicates the store is closed in Ottawa, Monday March 23, 2020. The Canadian Federation of Independent Business is raising its estimate for the number of businesses that are considering the possibility of closing permanently. THE CANADIAN PRESS/Adrian Wyld
Small business struggling amid COVID-19 pandemic looks for aid in Liberals’ budget

President Dan Kelly said it is crucial to maintain programs to help businesses to the other side of the pandemic

The National Security and Intelligence Committee of Parliamentarians says that includes attempts to steal Canadian research on COVID-19 and vaccines, and sow misinformation. (AP Photo/Esteban Felix)
Intelligence committee warns China, Russia targeting Canadian COVID-19 research

Committee also found that the terrorist threat to Canada has shifted since its last such assessment

Part of the massive mess left behind in a Spallumcheen rental home owned by Wes Burden, whose tenants bolted from the property in the middle of the night. Burden is now facing a hefty cleaning and repair bill as a result. (Photo submitted)
Tenants disappear in the night leaving Okanagan home trashed with junk, feces

Spallumcheen rental rooms filled with junk, human and animal feces; landlord scared to rent again

Parliament Hill is viewed below a Canada flag in Gatineau, Quebec, Friday, Sept. 18, 2020. A new poll suggests most Canadians are feeling more grateful for what they have in 2020 as a result of COVID-19 pandemic.THE CANADIAN PRESS/Sean Kilpatrick
Canada’s greenhouse gas emissions increased slightly in 2019: report

2019 report shows Canada emitted about one million tonnes more of these gases than the previous year

Dr. E. Kwok administers a COVID-19 vaccine to a recipient at a vaccination clinic run by Vancouver Coastal Health, in Richmond, B.C., Saturday, April 10, 2021. THE CANADIAN PRESS/Jonathan Hayward
B.C. to register people ages 40+ for COVID-19 vaccines in April

Appointments are currently being booked for people ages 66 and up

Most Read