A nurse prepares to give the first COVID-19 vaccine to be distributed in Edmonton on Dec. 15, 2020. THE CANADIAN PRESS/Jason Franson

A nurse prepares to give the first COVID-19 vaccine to be distributed in Edmonton on Dec. 15, 2020. THE CANADIAN PRESS/Jason Franson

Experts say stretching out time between COVID-19 vaccine doses in Alberta reasonable

Pfizer-BioNTech vaccine’s label says doses should be given 21 days apart and Moderna’s calls for a 28-day gap

Infectious disease experts say it makes sense for Alberta to stretch the amount of time between first and second doses beyond what’s spelled out on the labels of the two approved COVID-19 vaccines.

“I think it makes practical sense for the short term,” said Dr. Jim Kellner, a researcher and professor with the University of Calgary’s Cumming School of Medicine.

Dr. Lynora Saxinger, associate professor with the University of Alberta’s Department of Medicine, called the move “completely justifiable,” though she understands why some people are worried that the practice hasn’t been studied.

The Pfizer-BioNTech vaccine’s label says doses should be given 21 days apart and Moderna’s calls for a 28-day gap.

Dr. Deena Hinshaw, Alberta’s chief medical officer of health, said Tuesday the province is allowing doses to be booked up to 42 days apart, though long-term care residents will still receive theirs in the shorter window.

She said it wasn’t an easy decision.

“If we were to save half of every vaccine shipment for those who need a second dose, we would be dramatically reducing the total number of Albertans who could benefit from the early protection,” she said.

The National Advisory Committee on Immunization says prolonging the wait to 42 days is acceptable in places where there’s high community transmission, strain on the health-care system and limited vaccine supply — as is the case in Alberta.

Health Minister Tyler Shandro said Wednesday on Twitter that due to a shortage of supply, about 2,000 planned vaccinations for continuing care residents did not happen this week. The number of available appointments was also reduced in some areas.

There were 820 Albertans hospitalized with COVID-19 as of Wednesday, including 137 in intensive care. There were also 875 new cases detected over the past day and 5.3 per cent of tests came back positive.

Kellner, who is part of the national COVID-19 Immunity Task Force and also advises on provincial panels, said the longer timeline would be “reasonable” until the end of February, when Ottawa expects to significantly ramp up deliveries to the provinces.

But he said it’s not something he’d recommend doing indefinitely without further evidence.

“People are trying to balance doing the right thing for every individual who is in need of vaccine and … doing the right thing for the greater good for the whole population. And that’s always a challenge.”

Saxinger said while there’s little direct evidence about altering the vaccine dose schedule, experience with other vaccines suggests it’s not a problem. In some cases, immune responses benefit from a longer wait, she said.

“You have a bit of a more mature memory response to it.”

Data suggest both approved vaccines are 92 per cent effective two weeks after the first doses, but it’s not clear how long that protection lasts.

After a second dose, protection rises to 94.5 for the Pfizer-BioNTech vaccine and 94 per cent with the Moderna one.

Saxinger added that on average, antibody levels from the first dose are about four times higher than in those who recovered from COVID-19.

“Those things together are pretty reassuring,” she said, adding it’s “extremely” unlikely antibody levels that high would drop quickly in a matter of weeks.

She said modelling has been done of different scenarios.

“How many lives do you save if you give more first doses and circle back with the second dose, versus going for the very strict time schedule that’s been studied more thoroughly?” she said.

“All the models have shown that you save more lives with a bit of flexibility on the second dose timing.”

Health officials in Manitoba and Saskatchewan said they’re sticking with the time frame set out on the vaccine manufacturers’ labels for now. British Columbia plans to give the second shots 35 days later. Quebec has not set out a timeline for its follow-up doses.

Lauren Krugel, The Canadian Press

Like us on Facebook and follow us on Twitter.

Want to support local journalism? Make a donation here.

Coronavirus

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

Just Posted

An x-ray tech demonstrates the new equipment in use. (Photo Submitted)
New diagnostic equipment now operational at Sylvan Lake AACS

In August it was announced that Stephen and Jacqueline Wuori donated $850,000 to AACS

People skate on a lake in a city park in Montreal, Sunday, January 10, 2021. THE CANADIAN PRESS/Graham Hughes
The end of hugs: How COVID-19 has changed daily life a year after Canada’s 1st case

Today marks the one year anniversary of COVID-19 landing in Canada

SARS-CoV-2 virus particles, which causes COVID-19, emerge from the surface of cells isolated from a patient in the U.S. and cultured in a lab in a 2020 electron microscope image. THE CANADIAN PRESS/AP-HO, National Institute of Allergy and Infectious Diseases - Rocky Mountain Laboratories
Alberta adds 463 new COVID-19 cases on Sunday

The central zone has 818 active cases

As of Friday, Alberta has under 10,000 active COVID-19 cases. (Image courtesy CDC)
Alberta identifies 573 new COVID-19 cases, 13 deaths on Saturday

There are currently 9,727 active cases of the virus in the province

As of Friday, Alberta has under 10,000 active COVID-19 cases. (Image courtesy CDC)
Three new COVID-19 deaths in Central zone, Alberta under 10,000 active cases

The Central zone sits at 849 active cases, with 52 people in hospital and 10 in the ICU.

Terrance Josephson of the Princeton Posse, at left, and Tyson Conroy of the Summerland Steam clash during a Junior B hockey game at the Summerland Arena in the early spring of 2020. (John Arendt - Summerland Review)
QUIZ: How much do you know about hockey?

Test your knowledge of Canada’s national winter sport

Black Press file photo
Wetaskiwin RCMP investigate fatal pedestrian collision

A 37-year-old man from Maskwacis has died in hospital as a result of his injuries.

A registered nurse prepares a dose of the Moderna COVID-19 vaccine in Halifax on Monday, Jan. 11, 2021. Yukon’s Minister of Community Services, John Streiker, says he’s outraged that a couple from outside the territory travelled to a remote community this week and received doses of COVID-19 vaccine. THE CANADIAN PRESS/Andrew Vaughan-POOL
Couple charged after travelling to Yukon to get COVID-19 vaccine

The maximum fine under the emergency measures act is $500, and up to six months in jail

Metis Nation of B.C. President Clara Morin Dal Col poses in this undated handout photo. The Metis Nation of B.C. says Dal Col has been suspended from her role as president. The Metis Nation of B.C. says Dal Col has been suspended from her role as president. THE CANADIAN PRESS/HO, Metis Nation of B.C. *MANDATORY CREDIT*
Metis Nation of B.C. suspends president, citing ‘breach’ of policies, procedures

Vice-president Lissa Smith is stepping in to fill the position on an acting basis

Prime Minister Justin Trudeau speaks in the in the House of Commons on Parliament Hill in Ottawa on Thursday, Dec. 3, 2020. THE CANADIAN PRESS/Justin Tang
Payette shouldn’t get same benefits as other ex-governors general: O’Toole

Former governors general are entitled to a pension and also get a regular income paid to them for the rest of their lives

A woman injects herself with crack cocaine at a supervised consumption site Friday, Jan. 22, 2021 in Ottawa. THE CANADIAN PRESS/Adrian Wyld
Drug users at greater risk of dying as services scale back in second wave of COVID-19

It pins the blame largely on a lack of supports, a corrupted drug supply

RCMP. (Phil McLachlan - Black Press Media)
Blackfalds RCMP investigate fatal collision

Preliminary investigation revealed a south bound pickup truck collided with an eastbound car

Jennifer Cochrane, a Public Health Nurse with Prairie Mountain Health in Virden, administers the COVID-19 vaccine to Robert Farquhar with Westman Regional Laboratory, during the first day of immunizations at the Brandon COVID-19 vaccination supersite in Brandon, Man., on Monday, January 18, 2021. THE CANADIAN PRESS/Tim Smith - POOL
Top doctor urges Canadians to keep up with COVID measures, even as vaccines roll out

More than 776,606 vaccines have been administered so far

Dr. Jerome Leis and Dr. Lynfa Stroud are pictured at Sunnybrook Hospital in Toronto on Thursday, January 21, 2021.THE CANADIAN PRESS/Frank Gunn
‘It wasn’t called COVID at the time:’ One year since Canada’s first COVID-19 case

The 56-year-old man was admitted to Toronto’s Sunnybrook Health Sciences Centre

Most Read