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

Elvira D’Angelo, 92, waits to receive her COVID-19 vaccination shot at a clinic in Montreal, Sunday, March 7, 2021, as the COVID-19 pandemic continues in Canada and around the world. THE CANADIAN PRESS/Graham Hughes
110 new cases of COVID-19 in Interior Health

Provincial health officers announced 1,005 new cases throughout B.C.

Tala MacDonald, a 17-year-old student at Mount Sentinel Secondary who is also a volunteer firefighter, has won the $100,000 Loran Scholarship. Photo: Submitted
West Kootenay student wins $100K scholarship

Tala MacDonald is one of 30 Canadians to receive the Loran Scholarship

Montrose resident Kimba McLean has hiked Antenna Trail every day since October and counting. Photo: Jim Bailey
Montrose man makes daily trek up Antenna Trail

Kimba McLean put on more than 800-km hiking Antenna Trail every day for the past six months

Kristian Camero and Jessica Wood, seen here, co-own The Black Cauldron with Stephen Barton. The new Nelson restaurant opened earlier this month while indoor dining is restricted by the province. Photo: Tyler Harper
A restaurant opens in Nelson, and no one is allowed inside

The Black Cauldron opened while indoor dining is restricted in B.C.

First-year Selkirk College student Terra-Mae Box is one of many talented writers who will read their work at the Black Bear Review’s annual (virtual) launch on April 22. Photo: Submitted
Vancouver resident Beryl Pye was witness to a “concerning,” spontaneous dance party that spread throughout social groups at Kitsilano Beach on April 16. (Screen grab/Beryl Pye)
VIDEO: Dance party erupts at Vancouver’s Kitsilano Beach to the dismay of onlookers

‘It was a complete disregard for current COVID-19 public health orders,’ says Vancouver resident Beryl Pye

Pall Bearers carrying the coffin of the Duke of Edinburgh, followed by the Prince of Wales, left and Princess Anne, right, into St George’s Chapel for his funeral, at Windsor Castle, in Windsor, England, Saturday April 17, 2021. (Danny Lawson/Pool via AP)
Trudeau announces $200K donation to Duke of Edinburgh award as Prince Philip laid to rest

A tribute to the late prince’s ‘remarkable life and his selfless service,’ the Prime Minister said Saturday

B.C. homeowners are being urged to take steps to prepare for the possibility of a flood by moving equipment and other assets to higher ground. (J.R. Rardon)
‘Entire province faces risk’: B.C. citizens urged to prepare for above-average spring flooding

Larger-than-normal melting snowpack poses a threat to the province as warmer weather touches down

Vancouver-based Doubleview Gold Corp. is developing claims in an area north of Telegraph Creek that occupies an important place in Tahltan oral histories, said Chad Norman Day, president of the Tahltan Central Government. (THE CANADIAN PRESS/HO)
B.C. Indigenous nation opposes mineral exploration in culturally sensitive area

There’s “no way” the Tahltan would ever support a mine there, says Chad Norman Day, president of its central government

Stz’uminus Elder George Harris, Ladysmith Mayor Aaron Stone, and Stz’uminus Chief Roxanne Harris opened the ceremony. (Cole Schisler photo)
Symbolic red dresses rehung along B.C. highway after vandals tore them down

Leaders from Stz’uminus First Nation and the Town of Ladysmith hung new dresses on Sat. April 17

A Western toadlet crosses the centre line of Elk View Road in Chilliwack on Aug. 26, 2010. A tunnel underneath the road has since been installed to help them migrate cross the road. Saturday, April 24 is Save the Frogs Day. (Jenna Hauck/ Progress File)
Unofficial holidays: Here’s what people are celebrating for the week of April 18 to 24

Save the Frogs Day, Love Your Thighs Day and Scream Day are all coming up this week

Local carpenter Tyler Bohn embarked on a quest to create the East Sooke Treehouse, after seeing people build similar structures on a Discovery Channel show. (East Sooke Treehouse Facebook photo)
PHOTOS: B.C. carpenter builds fort inspired by TV’s ‘Treehouse Masters’

The whimsical structure features a wooden walking path, a loft, kitchen – and is now listed on Airbnb

The Attorney General’s Ministry says certain disputes may now be resolved through either a tribunal or the court system, pending its appeal of a B.C. Supreme Court decision that reduced the tribunal’s jurisdiction. (AP Photo/Mark J. Terrill)
Court of Appeal grants partial stay in ruling on B.C. auto injuries

B.C. trial lawyers challenged legislation brought in to cap minor injury awards and move smaller court disputes to the Civil Resolution Tribunal

An Extinction Rebellion Vancouver Island (XRVI) climate change event in 2019 saw a large crowd occupy the Johnson Street bridge. Black Press File Photo
‘In grief for our dying world’: B.C. climate activists embark on 4-day protest

Demonstrators will walk through Vancouver for the first two days before boarding a ferry Sunday morning

Most Read