A vial of some of the first 500,000 of the two million AstraZeneca COVID-19 vaccine doses that Canada has secured through a deal with the Serum Institute of India in partnership with Verity Pharma at a facility in Milton, Ont., on Wednesday, March 3, 2021. THE CANADIAN PRESS/Carlos Osorio - POOL

A vial of some of the first 500,000 of the two million AstraZeneca COVID-19 vaccine doses that Canada has secured through a deal with the Serum Institute of India in partnership with Verity Pharma at a facility in Milton, Ont., on Wednesday, March 3, 2021. THE CANADIAN PRESS/Carlos Osorio - POOL

Federal panel recommends 4-month gap between COVID vaccine doses due to limited supply

The recommendation applies to all COVID-19 vaccines currently approved in Canada

The National Advisory Committee on Immunization (NACI) is supporting B.C.’s decision to delay the second doses of COVID-19 vaccines by up to four months.

“NACI recommends that in the context of limited COVID-19 vaccine supply jurisdictions should maximize the number of individuals benefiting from the first dose of vaccine by extending the second dose of COVID-19 vaccine up to four months after the first,” the committee said in a decision published Wednesday (March 3).

The recommendation applies to all COVID-19 vaccines currently approved in Canada; Pfizer-BioNTech, Moderna and the newly approved AstroZeneca vaccine.

B.C. announced the decision to delay the second booster shot for four months on Monday, which health officials said could mean that all adults in the province could have their first dose by July.

READ MORE: Most B.C. adults could get their first COVID vaccine shot by July: health officials

Both provincial health officer Dr. Bonnie Henry and NACI said that its rationale was based on both the current available vaccine supply and data from other countries.

A study published by the University of Cambridge in the U.K., which has not yet been peer-reviewed, suggests that a single dose of the Pfizer-BioNTech vaccine can reduce the number of asymptomatic COVID-19 infections by 75 per cent.

In Israel, researchers studied the effects of a single dose of the same vaccine and published their findings in The Lancet medical journal, concluding that it was 85 per cent effective against symptomatic COVID-19 infections.

Also in The Lancet, a U.K. study found that the Oxford-AstraZeneca vaccine is 81 per cent effective when its second dose is given three months after the first, compared with 55 per cent efficacy after six weeks.

The national advisory committee noted that since the COVID-19 vaccines are still new, its unknown how long the protection of one or both doses lasts for.

“Experience with other multi-dose vaccines after a single dose suggests persistent protection could last for six months or longer in adolescents and adults,” NACI said in its statement. “Longer-term follow-up of clinical trial participants and those receiving vaccination in public programs will assist in determining the duration of protection following both one and two doses of vaccination.”

The national advisory committee added that it’s unknown how a delayed booster shot regime will affect the spread of variants of concern, including the U.K. and South African ones. However, NACI notes that there is “currently no evidence that an extended interval between doses will either increase or decrease the emergence of variants of concern.”

The committee noted that all three currently approved vaccines have shown “promising early result” against the U.K. variant B.1.1.7.

READ MORE: COVID-19 wage and rent subsidies, lockdown support to be extended until June

– with files from The Canadian Press


@katslepian

katya.slepian@bpdigital.ca

Like us on Facebook and follow us on Twitter.

Want to support local journalism during the pandemic? Make a donation here.

Coronavirusvaccines

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

Just Posted

As of Friday, Alberta has under 10,000 active COVID-19 cases. (Image courtesy CDC)
Alberta reports 2,271 new COVID-19 cases, Red Deer cases rise slightly

Across Alberta, there are 666 people in hospital with COVID-19, including 146 in the ICU

Alberta Health Services locked the Whistle Stop Cafe at Mirror on Wednesday morning after owner Christopher Scott refused to comply with health orders.
Photo by Paul Cowley/Advocate staff
AHS shuts down Whistle Stop Cafe for defying health orders

Health inspectors and RCMP locked doors early Wednesday

Premier Jason Kenney (File photo by THE CANADIAN PRESS)
A vial of Oxford-AstraZeneca COVID-19 vaccine is seen at a facility in Milton, Ont., on Wednesday, March 3, 2021. An Alberta woman in her 50s has died from a rare blood clot disorder after receiving the AstraZeneca vaccine. THE CANADIAN PRESS/Carlos Osorio - POOL
Alberta confirms blood clot disorder death linked to AstraZeneca vaccine

Both AstraZeneca and Johnson & Johnson vaccines have been linked to VITT in a very small number of cases

Premier Jason Kenney says with COVID-19 numbers still rising, the province’s health-care system will be tested in the coming weeks. (photography by Winston Pon/Office of the Premier)
‘Please stay home’: Kenney imposes new COVID-19 restrictions

New measures will be in place for at least three weeks

FILE - In this March 3, 2021, file photo, a vial of the Johnson & Johnson COVID-19 vaccine is displayed at South Shore University Hospital in Bay Shore, N.Y. (AP Photo/Mark Lennihan, File)
Johnson & Johnson COVID vaccine can be given to adults 30+ who can’t wait for mRNA: NACI

Panel says single shot vaccine can be especially useful for populations unable to return for second shot

B.C.’s provincial health officer, Dr. Bonnie Henry. THE CANADIAN PRESS/Jonathan Hayward
Dip in COVID-19 cases with 572 newly announced in B.C.

No new deaths have been reported but hospitalized patients are up to 481, with 161 being treated in intensive care

A dose of the Pfizer COVID-19 vaccination is prepared at a mobile clinic for members of First Nations and their partners, in Montreal, Friday, April 30, 2021. THE CANADIAN PRESS/Ryan Remiorz
Pfizer-BioNTech vaccine approved for kids 12 to 15 years old in Canada

The vaccine was previously authorized for anyone at least 16 years of age or older

Prime Minister Justin Trudeau listens to speakers appearing by video during a news conference in Ottawa on Tuesday May 4, 2021. THE CANADIAN PRESS/Adrian Wyld
Canada will align policy on ‘vaccine passports’ with international allies: Trudeau

Trudeau says Canadians could begin travelling outside the country again by summer

Ranging from 11 to 20 in age and representing seven provinces and one territory, the plaintiffs are appealing a Supreme Court judge’s decision to dismiss their lawsuit last fall. (David Suzuki Foundation)
15 youths not backing down in their fight to sue Ottawa over climate change inaction

The group has filed an appeal after their lawsuit was struck down by a Federal Court judge last fall

A 2021 census questionnaire. (Black Press Media file photo)
2021 census responses due May 11

By law, every household must complete a census questionnaire

Calgary Mayor Naheed Nenshi attends a senior’s home in Calgary on Tuesday, April 14, 2020, amid a worldwide COVID-19 pandemic. Nenshi says he’s frustrated to hear that tickets given to people for breaching COVID-19 public health orders are being thrown out in the courts.THE CANADIAN PRESS/Jeff McIntosh
‘Incredibly frustrating:’ Calgary mayor wants courts to uphold COVID-19 measures

Large groups without masks have been gathering in Calgary public spaces in protest of health measures

Jose Marchand prepares Pfizer COVID-19 vaccination doses at a mobile clinic for members of First Nations and their partners, in Montreal, Friday, April 30, 2021. The National Advisory Committee on Immunization is coming under fire after contradicting the advice Canadians have been receiving for weeks to take the first vaccine against COVID-19 that they’re offered. THE CANADIAN PRESS/Ryan Remiorz
NACI advice on ‘preferred vaccines’ for COVID-19 sparks confusion, anger

Panel said that people who can wait for an mRNA vaccine should do so

Michael Bonin, 20, from Alberta, was discovered deceased on Peers Creek Forest Service Road north of Hope on April 20, 2017. (Black Press Media)
1 of 3 accused in 2017 murder of Alberta man pleads guilty, sentenced to life in prison

Joshua Fleurant pleaded guilty in a Kelowna courtroom to the second-degree murder of Michael Bonin

Most Read