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 screenshot from a local Instagram account video. The account appeared to be frequented by Mission students, and showed violent videos of students assaulting and bullying other students.
Parents, former students describe ‘culture of bullying’ in Mission schools

Nearly two dozen voices come forward speaking of abuse haunting the hallways

A door is boarded up following a fire at Pho Xuan restaurant on Yale Road on Friday, Jan. 22, 2021. (Jenna Hauck/ Chilliwack Progress)
UPDATE: Early morning fire at vacant Chilliwack restaurant was deliberately set

Fire erupted north of the Yale Road overpass at Pho Xuan, which was permanently closed

The 4th Annual Fraser Valley Marches for Women March is virtual this year, and this file shot depicts speeches from the first march from Jan. 20, 2018. (Jennifer Feinberg/Chilliwack Progress file)
Video on women’s march emphasizes that violence against women increasing

Key messages from Chilliwack women leaders as the FV Marches for Women March goes virtual

Officers investigate the scene after a pedestrian was struck and killed on Friday morning. (Ben Lypka/Abbotsford News)
Male pedestrian, 37, killed in Abbotsford after being struck by vehicle

Collision took place in 31800 block of South Fraser Way on Friday morning

(Black Press Media files)
Snowfall expected for Lower Mainland on Saturday night, Sunday morning

2 to 5 cm of snow predicted Metro Vancouver, according to Environment Canada

Toronto Public Health nurse Lalaine Agarin sets up for mass vaccination clinic in Toronto, Jan. 17, 2021. B.C. is set to to begin its large-scale immunization program for the general public starting in April. THE CANADIAN PRESS/Frank Gunn
B.C.’s COVID-19 mass vaccinations expected to start in April

Clinics to immunize four million people by September

Surrey provincial court. (File photo: Tom Zytaruk)
New COVID-19 protocols set for provincial courthouses

The new rules were issued on Jan. 21, and took effect immediately

Police in Vancouver looking for male suspect who allegedly spat and attacked a store manager for not wearing a mask, at 7-Eleven near Alma Street and West 10th Avenue just before noon on Dec. 17, 2020. (Vancouver police handout)
VIDEO: Man spits on 7-Eleven manager over mask rule, sparking Vancouver police probe

‘Unfortunately, the store manager sustained a cut to his head during the assault’

The Vancouver-based SAR team successfully rescued two lost snowshoers off of the west side of Tim Jones Peak in the early morning of Monday, Jan. 19. (North Shore Rescue photo)
B.C.’s busiest SAR team raises alarm after 2021 begins with fatality, multiple rescues

‘People beyond ski resort areas of Seymour, Grouse, and Cypress go without cell reception,’ SAR warns

Post-COVID-19 recovery clinic in Surrey, at Jim Pattison Outpatient Care and Surgery Centre. (Photo: Fraser Health)
Surrey to host 1 of 3 post-COVID recovery clinics in Lower Mainland

The Jim Pattison Outpatient Care and Surgery Centre is located at 9750 140th Street

Competitors make their way through the course at the 2019 Canadian Cross Country Championships, which was hosted by Abbotsford in 2019. (File photo)
Abbotsford to host 2023 Canadian Cross Country Championships

Clearbrook Park last hosted the event in 2019, Ottawa hosting 2021 and 2022 races

Police are searching for an alleged sex offender, Nicole Edwards, who they say has not returned to her Vancouver halfway house. (Police handout)
Police hunt for woman charged in ‘horrific’ assault who failed to return to Surrey halfway house

Call 911 immediately if you see alleged sex offender Nicole Edwards, police say

Joe Biden, then the U.S. vice-president, and Prime Minister Justin Trudeau take their seats at the start of the First Ministers and National Indigenous Leaders meeting in Ottawa, Friday, Dec. 9, 2016. THE CANADIAN PRESS/Adrian Wyld
Trudeau, Biden to talk today as death of Keystone XL reverberates in Canada

President Joe Biden opposed the Keystone XL expansion as vice-president under Barack Obama

Prince Edward Island’s provincial flag flies on a flag pole in Ottawa, Friday July 3, 2020. A lozenge plant in Prince Edward Island has laid off 30 workers, citing an “almost non-existent” cold and cough season amid COVID-19 restrictions. THE CANADIAN PRESS/Adrian Wyld
‘Almost non-existent’ cold and cough season: P.E.I. lozenge plant lays off 30 workers

The apparent drop in winter colds across the country seems to have weakened demand for medicine and natural remedies

Most Read