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

A sign indicating a COVID-19 testing site is displayed inside a parking garage in West Nyack, N.Y., Monday, Nov. 30, 2020. The site was only open to students and staff of Rockland County schools in an effort to test enough people to keep the schools open for in-person learning. (AP Photo/Seth Wenig)
4 more deaths, 54 new cases of COVID-19 in Interior Health

This brings the total to 66 deaths in the region

Surrey RCMP are investigating after a pedestrian was struck and killed at 183 Street and Highway 10 Friday night. (File photo)
Grand Forks RCMP Cst. Eileen O’Mahony, left, and Grand Forks Fire/Rescue Dep. Chief Stephane Dionne report back to their departments at the scene of Tuesday’s single-vehicle rollover on Hwy. 3, west of Grand Forks. Photo: Laurie Tritschler
Driver leaves Hwy. 3 rollover through broken window, west of Grand Forks

Grand Forks RCMP taped off the scene at around 11 a.m. Tuesday, Jan. 26

Castlegar Sculpturewalk 2020 – 10 Year Anniversary Sand Sculpture. (Submitted/CBT)
CBT arts and culture grant program now accepting applications

Apply through the Kootenay Columbia Cultural Alliance

The Regional District of Kootenay Boundary reported to B.C’s housing ministry in November that local opposition has ‘impacted’ potential housing solutions in Grand Forks. File photo.
‘Loud voices of opposition’ hiding support for affordable housing solutions in Grand Forks, says RDKB report

The report noted ‘heightened anxiety, division, and polarity’ has ‘impacted’ chances to house vulnerable residents

Dr. Penny Ballem, a former deputy health minister, discusses her role in leading B.C.’s COVID-19 vaccination program, at the B.C. legislature, Jan. 22, 2021. (B.C. government)
B.C. holds steady with 407 new COVID-19 cases Tuesday

14 deaths, no new outbreaks in the health care system

A Cessna 170 airplane similar to the one pictured above is reported to be missing off the waters between Victoria and Washington State. Twitter photo/USCG
Canadian, American rescue crews searching for missing aircraft in waters near Victoria

The search is centered around the waters northeast of Port Angeles

Interior Health reported two more COVID-19 deaths at Sunnybank Retirement Center in Oliver Tuesday, Jan. 26, 2021. (File photo)
COVID-19 claims lives of two more South Okanagan care home residents

Five residents of the Oliver care home have died since the outbreak was first declared

Jonathon Muzychka and Dean Reber are wanted on Canada-wide warrants. (Courtesy of Victoria Police Department)
Convicted killer, robber at large after failing to return to facility: Victoria police

Dean Reber, 60, and Jonathon Muzychka, 43, may be together

B.C. Premier John Horgan listens during a postelection news conference in Vancouver on Sunday, Oct. 25, 2020. THE CANADIAN PRESS/Darryl Dyck
30% of B.C. recovery benefit applications held up in manual review

The province says 150 staff have been reassigned to help with manually reviewing applications

Adam Dergazarian, bottom center, pays his respect for Kobe Bryant and his daughter, Gianna, in front of a mural painted by artist Louie Sloe Palsino, Tuesday, Jan. 26, 2021, in Los Angeles. (AP Photo/Jae C. Hong)
Kobe Bryant’s presence remains strong a year after his death

Tuesday marks the grim anniversary of the crash that took their lives

Modelling of predicted transmission growth from the B117 COVID-19 variant in British Columbia. (Simon Fraser University)
COVID-19 variant predicted to cause ‘unmanageable’ case spike in B.C: report

SFU researchers predict a doubling of COVID-19 cases every two weeks if the variant spreads

The Brucejack mine is 65 km north of Stewart in northwestern B.C. (Pretivm Photo)
B.C. mine executives see bright gleam in post-COVID future

Low carbon drives demand for copper, steelmaking coal

In this Dec. 18, 2020 photo, pipes to be used for the Keystone XL pipeline are stored in a field near Dorchester, Neb.  THE CANADIAN PRESS/AP-Chris Machian /Omaha World-Herald via AP
Canadians divided over Keystone pipeline, despite U.S. president’s permit pullback

Two-thirds of Canadians think Biden’s decision was a “bad thing” for Alberta

Most Read