A vial of the Oxford-AstraZeneca vaccine is seen at a mass COVID-19 vaccination clinic in Calgary, Alta., on April 22, 2021.Jeff McIntosh/The Canadian Press
Mayors in an Ontario COVID-19 hot spot are joining calls for the government to reduce the vaccine dosing interval for Oxford-AstraZeneca recipients as a more infectious variant spreads in the province.
Residents who got a first shot of AstraZeneca currently must wait 12 weeks between doses in Ontario, but other provinces have shortened the gap to eight weeks.
Brampton Mayor Patrick Brown wrote to the Premier and Health Minister on Friday asking that Ontario follow suit with an eight-week gap between doses.
“Residents should have the choice to be fully immunized sooner so they have better protection against variants,” wrote Mr. Brown, whose community is part of Peel Region, where the Delta variant has been spreading. “Help us crush COVID in Peel!”
Mr. Brown’s Mississauga counterpart, Mayor Bonnie Crombie, also wrote a letter calling for a shorter dose interval. She said residents who took a first shot of the AstraZeneca vaccine helped curb the third wave of COVID-19 and are now being left less protected.
COVID-19 is caused by a virus called SARS-CoV-2, and as it spread around the world, it mutated into new forms that are more quickly and easily transmitted through small water droplets in the air. Canadian health officials are most worried about variants that can slip past human immune systems because of a different shape in the spiky protein that latches onto our cells. The bigger fear is that future mutations could be vaccine-resistant, which would make it necessary to tweak existing drugs or develop a new “multivalent” vaccine that works against many types, which could take months or years.
Not all variants are considered equal threats: Only those proven to be more contagious or resistant to physical-distancing measures are considered by the World Health Organization to be “variants of concern.” Five of these been found in Canada so far. The WHO refers to them by a sequence of letters and numbers known as Pango nomenclature, but in May of 2021, it also assigned them Greek letters that experts felt would be easier to remember.
ALPHA (B.1.1.7)
- Country of origin: Britain
- Traits: Pfizer-BioNTech and Moderna vaccines are still mostly effective against it, studies suggest, but for full protection, the booster is essential: With only a first dose, the effectiveness is only about 66 per cent.
- Spread in Canada: First detected in Ontario’s Durham Region in December. It is now Canada’s most common variant type. Every province has had at least one case; Ontario, Quebec and the western provinces have had thousands.
BETA (B.1.351)
- Country of origin: South Africa
- Traits: Some vaccines (including Pfizer’s and Oxford-AstraZeneca’s) appear to be less effective but researchers are still trying to learn more and make sure future versions of their drugs can be modified to fight it.
- Spread in Canada: First case recorded in Mississauga in February. All but a few provinces have had at least one case, but nowhere near as many as B.1.1.7.
GAMMA (P.1)
- Country of origin: Brazil
- Traits: Potentially able to reinfect people who’ve recovered from COVID-19.
- Spread in Canada: B.C. has had hundreds of cases, the largest known concentration of P.1 outside Brazil. More outbreaks have been detected in Ontario and the Prairies.
DELTA (B.1.617 AND B.1.617.2)
- Country of origin: India
- Traits: Spreads more easily. Single-dosed people are less protected against it than those with both vaccine doses.
- Spread in Canada: All but a few provinces have recorded cases, but B.C.’s total has been the largest so far.
LAMBDA (C.37)
- Country of origin: Peru
- Traits: Spreads more easily. Health officials had been monitoring it since last August, but the WHO only designated it a variant of concern in June of 2021.
- Spread in Canada: A handful of travel-related cases were first detected in early July.
If I’m sick, how do I know whether I have a variant?
Health officials need to genetically sequence test samples to see whether it’s the regular virus or a variant, and not everyone’s sample will get screened. It’s safe to assume that, whatever the official variant tallies are in your province, the real numbers are higher. But for your purposes, it doesn’t matter whether you contract a variant or not: Act as though you’re highly contagious, and that you have been since before your symptoms appeared (remember, COVID-19 can be spread asymptomatically). Self-isolate for two weeks. If you have the COVID Alert app, use it to report your test result so others who may have been exposed to you will know to take precautions.
Need more answers? Email audience@globeandmail.com
Canada vaccine tracker: How many COVID-19 doses have been administered so far?
When do COVID-19 restrictions ease in my province? A guide to the rules across Canada
COVID-19 vaccine questions answered: dose mixing, life after the vaccine and more
“They are watching family members and friends register [for] and receive second doses, and it is simply not fair,” Ms. Crombie wrote in her letter Friday.
Calls have been growing for Ontario to shorten the dosing interval for AstraZeneca recipients as the more infectious Delta variant spreads. Doctors, politicians and those who got AstraZeneca have been urging the government to change its position.
Scientific evidence shows people with one vaccine dose are less protected against the Delta variant.
An online petition asking the government to shorten the interval to eight weeks for those who got AstraZeneca had more than 2,800 signatures as of Friday afternoon.
Gareth Williams of Burlington, Ont., said he started the petition after he grew frustrated watching second shots get moved up for others.
“We seem to be forgotten,” Williams said by phone.
“I think a lot of people are in the same boat as me. They got it themselves and a lot of other people who have family members that have received it and are frustrated.”
Starting Monday, residents of seven Delta variant hot spots who got a first dose of a COVID-19 vaccine on or before May 9 and book accelerated second doses. Those aged 70 and older can already book faster second shots.
AstraZeneca recipients, however, must still wait 12 weeks for their second shot, whether they opt for another dose of the same vaccine or a shot of a mRNA vaccine.
Ontario has maintained that 12 weeks is the most effective dosing interval for AstraZeneca, with Health Minister Christine Elliott calling it the “gold standard” on Thursday.
The province’s associate chief medical officer of health has noted, however, that the province is reviewing data on the issue.
“We’re very actively looking now at the data with Public Health Ontario and are actively considering the intervals for those individuals,” Dr. Barbara Yaffe said Thursday.
The head of the Ontario Pharmacists Association said AstraZeneca recipients should be able to choose whether to get an earlier second shot in light of the spreading Delta variant or wait for 12 weeks to become fully vaccinated.
“The benefit of getting people fully vaccinated outweighs any potential decrease in optimal efficacy,” Justin Bates wrote on Twitter.
Ontario stopped administering first doses of AstraZeneca in May over what it said was an increased risk of rare but serious blood clots. It had given out nearly a million doses of the vaccine by that point.
With files from Denise Paglinawan.
Sign up for the Coronavirus Update newsletter to read the day’s essential coronavirus news, features and explainers written by Globe reporters and editors.
This content appears as provided to The Globe by the originating wire service. It has not been edited by Globe staff.