More than half of Canadians have now received at least one COVID-19 vaccine dose

MONTREAL — Canada’s race toward widespread COVID-19 immunity reached a milestone on Saturday, as numbers showed half the national population has received at least one dose of vaccine meant to protect against the virus.

The news came hours after the country’s top vaccine advisors issued further guidance on second doses, potentially clearing the way to mix and match shots of the same overall type. 

Data compiled from federal, provincial and territorial health authorities showed more than 20.6 million doses have been injected across the country as of Saturday, with 50.01 per cent of the population getting at least one jab.

Canada edged ahead of the United States in its proportion of inoculations on Thursday, when just over 48 per cent of Americans had received their first dose.

Raywat Deonandan, an epidemiologist with the University of Ottawa, said the 50-per-cent threshold represents an important marker for Canada, adding such a visible sign of progress stands to offer Canadians a much-needed psychological boost. 

“It is a milestone,” Deonandan said. “It’s like: Hey, we as a society have passed an important point in this marathon and we can almost see the finish line. And even though we’re all tired, we’re going to sprint to the end together.”

Nonetheless, Canada remains far back of the pack in the full-vaccination race, with about four per cent of Canadians fully immunized, according to Health Canada.

The one-dose milestone marks a dramatic turnaround for Canada, which just a month ago remained well behind global leaders such as the U.S., the United Kingdom, Israel and Chile.

Federal figures show an average of about 330,000 people joined the vaccinated group each day over the past week.

Canada’s chief public health officer said current case numbers are about 30 per cent lower than they were in mid-April when the pandemic’s third wave crested.

Dr. Theresa Tam issued a statement Saturday saying strong public-health measures must remain in place where COVID-19 is circulating, particularly in light of Monday’s Victoria Day holiday that creates a long weekend across the country.

“As resurgences have followed social gatherings during past long weekends and holidays, maintaining precautions this long weekend remains critical for sustaining our progress,” she said.

Meanwhile, the National Advisory Committee on Immunization has updated its guidance on second shots, recommending that patients receive the same vaccine in round two as they did at their first appointment.

But if that vaccine is unavailable, NACI suggests taking Johnson & Johnson in place of Oxford-AstraZeneca, and taking Moderna in place of Pfizer-BioNTech — both are mRNA vaccines — or vice-versa.

When it comes to the viral vector vaccines AstraZeneca and J&J, however, the question is moot for the time being. Plans to distribute the initial 300,000-dose shipment of Johnson & Johnson remain on hold after Health Canada learned parts of the batch were manufactured at a Maryland facility mired in quality-control problems.

An mRNA vaccine in place of a second AstraZeneca shot may be an option, but NACI is waiting on more data.

A Spanish study released initial results last week showing a second dose of Pfizer for AstraZeneca recipients produced a stronger immune response, but more information is pending.

A U.K. study earlier this month found that the same sequence produced some stronger initial side effects, but that they were temporary and mixing the vaccines was deemed safe. Further data on whether the blend yields similar or better results than two doses of the same vaccine is expected in a few weeks.

Matthew Tunis, executive secretary to NACI, told a parliamentary health committee Friday that AstraZeneca recipients should wait 12 weeks to get a second dose in order to elicit a stronger immune response. NACI has previously said that up to 16 weeks will suffice.

Canada’s earliest AstraZeneca recipients got their first dose in mid-March, which means a few weeks remain before the three-month marker hits. The window leaves some time for more evidence to come in on vaccine interchangeability.

The mounting percentage of vaccinated Canadians hasn’t eased concern across the board, nor had an immediate impact on lowering case counts in some hot spots.

Manitoba reported 476 new COVID-19 cases and six deaths on Saturday as the percentage of people testing positive, averaged over five days, continued to climb.

Premier Brian Pallister has asked the U.S. government to give the province’s vaccine drive a boost by allowing individual states like North Dakota to begin exporting shots on their own.

Pallister said the U.S. has exported vaccines on a country-to-country basis, but argued allowing individual states to do so could speed up the process.

He said he has written to U.S. President Joe Biden on the issue, but has not yet received a response.

“The vaccines are sitting in freezers miles away (in North Dakota). We have people here waiting and we need those vaccines up here,” Pallister said.

In Nova Scotia, officials announced community spread of COVID-19 in both the central region and Sydney, saying they will increase testing in “areas of concern.”

Nova Scotia also marked an immunization milestone Saturday, administering its 500,000th dose of vaccine.

But it was Ontario that led the recent surge in vaccinations, administering more than 190,000 shots on Friday. The province logged 1,794 new infections on Saturday, along with 20 virus-related deaths.

Quebec, meanwhile, recorded the lowest number of new cases since September when it added 505 to its provincial count.

Infections also ticked downward in Nova Scotia, which reported 64 new cases and one associated death. Officials in Newfoundland and Labrador reported four new infections, while New Brunswick tallied two.

Further west, Saskatchewan reported 180 new cases on Saturday while Alberta logged 621 in addition to six new deaths. 

This report by The Canadian Press was first published May 22, 2021.

— With files from Mia Rabson in Ottawa, Steve Lambert in Winnipeg and Danielle Edwards in Halifax

Christopher Reynolds, The Canadian Press