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. Centre for Disease Control maps showing new COVID-19 cases by local health area for the week of April 4-10. (BCCDC image)
Parksville-Qualicum passes Nanaimo in new COVID-19 cases

Greater Victoria had more new cases than any other Island area: B.C. Centre for Disease Control

‘For Sale’ signs quickly turned to ‘Sold’ signs as record-high demand for housing meets record-low inventory. (Cole Schisler photo)
Multiple offers and unconditional sales rampant in Ladysmith housing market

Vancouver Island Real Estate Board Zone 3 director Susan Perrey says the market is ‘crazy all around’

From left to right: Vicki Barta, Bruce Ormond, Greg Heide, Gord McInnis, and Charles Harman rehearse via zoom for the upcoming radio play, “Visitor from Planet Zoltan”. (Submitted photo)
Radio plays prove successful for Ladysmith Little Theatre, four more in production

Ladysmith Little Theatre pivoted to producing radio plays during the pandemic

Two men were seen removing red dresses alongside the Island Highway in Oyster Bay. (Submitted photo)
Two men filmed removing red dresses from trees in Oyster Bay

Activists hung the dresses to raise awareness for Vancouver Island Murdered/Missing Women & Girls

Ladysmith’s Taylor Walters received the Terry Fox Humanitarian Award and is hard at work pursuing her Bachelor’s Degree in Human-Computer Interaction at Quest University. (Submitted photo)
Ladysmith teen receives Terry Fox Humanitarian Award for advocating equal access to STEM opportunities

‘Different people think differently and that’s so important for innovation,’ Taylor Walters says

A woman wears a protective face covering to help prevent the spread of COVID-19 as she walks past the emergency entrance of Vancouver General Hospital in Vancouver, B.C., Friday, April 9, 2021. COVID-19 cases have been on a steady increase in the province of British Columbia over the past week. THE CANADIAN PRESS/Jonathan Hayward
Top doctor warns B.C.’s daily cases could reach 3,000 as COVID hospitalizations surge

There are more than 400 people in hospital, with 125 of them in ICU

The father of Aaliyah Rosa planted a tree and laid a plaque in her memory in 2018. (Langley Advance Times files)
Final witness will extend Langley child murder trial into May or June

Lengthy trial began last autumn with COVID and other factors forcing it to take longer than expected

The corner of 96th Avenue and Glover Road in Fort Langley now has traffic signals, and new “touchless” signal activation buttons. (Matthew Claxton/Langley Advance Times)
Busy Fort Langley intersection gets ‘touchless’ crosswalk signals

The new traffic light started operation in April

A crossing guard stops traffic as students wearing face masks to curb the spread of COVID-19 arrive at Ecole Woodward Hill Elementary School, in Surrey, B.C., on Tuesday, February 23, 2021. A number of schools in the Fraser Health region, including Woodward Hill, have reported cases of the B.1.7.7 COVID-19 variant first detected in the U.K. THE CANADIAN PRESS/Darryl Dyck
COVID-infected students in Lower Mainland schools transmitting to 1 to 2 others: data

Eight to 13 per cent of COVID cases among students in the Lower Mainland were acquired in schools, B.C. says

An armed officer walks outside Cerwydden Care on Cowichan Lake Road near Skinner Road Wednesday, April 14 around 5:30 p.m. (Kevin Rothbauer/Citizen)
Police standoff at Duncan apartment ends peacefully

Officers surround building as homeowner held in apartment for nearly four hours by adult son

Norm Scott, president of Royal Canadian Legion Branch # 91, is disappointed the Legion does not qualify for COVID financial assistance from the provincial government. (Black Press Media file photo)
B.C.’s pandemic aid package passing Legion branches by

Federal non-profit status stymies provincial assistance eligibility

Latest modelling by public health shows cases generated by COVID-19 infections into places where it can spread quickly. (B.C. Centre for Disease Control)
Industrial sites, pubs, restaurants driving COVID-19 spread in B.C.

Infection risk higher in offices, retail, warehouses, farms

Hwy. 4 was shut down in both directions for 10 hours on March 23 as a rock bluff was blasted as part of Kennedy Hill’s ongoing construction. Commuters can expect five more 10 hour closures on five consecutive Wednesdays beginning April 28. (Photo courtesy of Ministry of Transportation and Infrastructure)
Five 10-hour Pacific Rim highway closures planned in the next 6 weeks

Closures needed for rock blasting as part of the Kennedy Hill Safety Improvement project.

Most Read