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

Sheriff Avory Chapman was last seen Jan. 20 on Wellington Avenue in Chilliwack. (RCMP)
RCMP look for missing man last seen in downtown Chilliwack

21-year-old Sheriff Avory Chapman has been missing since Jan. 20

A worker is seen throwing a chicken in an undercover video in 2017 filmed by California-based animal rights activists Mercy For Animals.
Fraser Valley chicken abuse trial delayed until February

Originally scheduled for a jury trial, Sofina and Chilliwack company now face judge alone

Chilliwack-Kent MLA Kelli Paddon funding Equity and Social Change Scholarships

One of the scholarships is open to any graduating student in the Chilliwack-Kent electoral district

Crews with Discovery Channel film as an Aggressive Towing driver moves a Grumman S2F Tracker aircraft around a 90-degree turn from its compound and onto the road on Saturday, Jan. 23, 2021. It was the “most difficult” part of the move for the airplane, one organizer said. (Jenna Hauck/ Chilliwack Progress)
VIDEO: Vintage military plane towed across Chilliwack over weekend

Grumman CP-121 Tracker’s eventual home the British Columbia Aviation Museum on Vancouver Island

Rose Sawka, 91, waves to her son through the window of a care home in Prince Rupert in October. Residents of the care home received their first vaccine dose Jan. 20. (K-J Millar/The Northern View)
B.C. care home visitor access to expand by March, Dix says

Staff, residents, essential visitors top priorities for vaccine

The trial of Harry Richardson began Monday at the Nelson courthouse. File photo
Trial of man accused of shooting RCMP officer in West Kootenay in 2019 begins

Harry Richardson is facing five charges in a Nelson courtroom

FILE – Canadian Prime Minister Justin Trudeau delivers his opening remarks at a news conference outside Rideau cottage in Ottawa, Tuesday, January 19, 2021. THE CANADIAN PRESS/Adrian Wyld
Vaccine CEO ‘very, very clear’ that Canada’s contracts will be honoured: Trudeau

Trudeau says he spoke to Moderna CEO on the morning of Jan. 26

Brad Windsor has been an advocate for years to get sidewalks installed along Milburn Drive in Colwood, but to no avail. He wants city council to commit to making Milburn a priority lane for sidewalk construction in the future. (Aaron Guillen/News Staff)
VIDEO: Dramatic crash caught on B.C. home security camera

Angry residents say video highlights need for sidewalks in B.C. residential neighbourhood

An independent review is underway at the Royal BC Museum after employees called out systemic, individual racism at the institution. (Twitter/RBCM)
Royal BC Museum faces allegations of systemic racism, toxic work environment

Formal investigation, survey and training launched at museum

In this May 23, 2012, file photo, an approximately 2-year-old female cougar runs away from a Washington Department of Fish and Wildlife trap after being released northeast of Arlington, Wash. A cougar has attacked and severely mauled a man in British Columbia. THE CANADIAN PRESS/AP-Mark Mulligan/The Daily Herald via AP
Cougar euthanized in B.C. after severely mauling a man north of Vancouver

Whistler RCMP officers were first on the scene and shot and killed a cougar prowling nearby

The SACH Community Hub team, from left to right: Upkar Singh Tatlay, Gary Thandi, Allysha Ram, Jassy Pandher, Harman Pander. (Submitted photo)
There’s help for South Asian men wrestling with drug addiction in Surrey

South Asian deaths related to toxic drugs increased by 255 per cent between 2015 and 2018

The Independent Investigations Office of BC (IIO) is looking into the death of man discovered Jan. 11 in east Maple Ridge. (Black Press files)
B.C.’s police watchdog investigating man’s death in Maple Ridge

Man was found dead Jan. 11 after recent contact with police

Chilliwack Law Courts. (Black Press file)
Man sentenced to 20 months for sexual offences involving a minor in Mission

Will Laws Clark was 22 and victim was 13 at time offences began

Most Read