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A vial of the AstraZeneca COVID-19 vaccine, at a facility in Milton, Ont., on March 3, 2021.Carlos Osorio/The Canadian Press

Canada’s expert vaccine panel said Tuesday there is now enough “real-world evidence” to show the Oxford-AstraZeneca COVID-19 shot is both safe and effective for seniors.

The decision from the National Advisory Committee on Immunization (NACI) reverses its advice from March 1, when a lack of data for seniors in AstraZeneca’s clinical trials prompted the panel to not recommend it be used for people over 65. It said seniors should instead be prioritized for shots from Pfizer-BioNTech and Moderna.

The new advice comes as authorities debate whether Canada is moving into a third wave of the pandemic, and investigate concerns about blood clots and AstraZeneca’s vaccine.

Dr. Marc Berthiaume, director of the medical sciences branch at Health Canada, said the department is following the issue but currently sees no evidence of a safety concern.

“If we do hear that there’s a specific risk, links to the AstraZeneca vaccine, then we will immediately take action,” he said in French.

Moderna, Pfizer, AstraZeneca or Johnson & Johnson: Which COVID-19 vaccine will I get in Canada?

Canada pre-purchased millions of doses of seven different vaccine types, and Health Canada has approved four so far for the various provincial and territorial rollouts. All the drugs are fully effective in preventing serious illness and death, though some may do more than others to stop any symptomatic illness at all (which is where the efficacy rates cited below come in).

PFIZER-BIONTECH

  • Also known as: Comirnaty
  • Approved on: Dec. 9, 2020
  • Efficacy rate: 95 per cent with both doses in patients 16 and older, and 100 per cent in 12- to 15-year-olds
  • Traits: Must be stored at -70 C, requiring specialized ultracold freezers. It is a new type of mRNA-based vaccine that gives the body a sample of the virus’s DNA to teach immune systems how to fight it. Health Canada has authorized it for use in people as young as 12.

MODERNA

  • Also known as: SpikeVax
  • Approved on: Dec. 23, 2020
  • Efficacy rate: 94 per cent with both doses in patients 18 and older, and 100 per cent in 12- to 17-year-olds
  • Traits: Like Pfizer’s vaccine, this one is mRNA-based, but it can be stored at -20 C. It’s approved for use in Canada for ages 12 and up.

OXFORD-ASTRAZENECA

  • Also known as: Vaxzevria
  • Approved on: Feb. 26, 2021
  • Efficacy rate: 62 per cent two weeks after the second dose
  • Traits: This comes in two versions approved for Canadian use, the kind made in Europe and the same drug made by a different process in India (where it is called Covishield). The National Advisory Committee on Immunization’s latest guidance is that its okay for people 30 and older to get it if they can’t or don’t want to wait for an mRNA vaccine, but to guard against the risk of a rare blood-clotting disorder, all provinces have stopped giving first doses of AstraZeneca.

JOHNSON & JOHNSON

  • Also known as: Janssen
  • Approved on: March 5, 2021
  • Efficacy rate: 66 per cent two weeks after the single dose
  • Traits: Unlike the other vaccines, this one comes in a single injection. NACI says it should be offered to Canadians 30 and older, but Health Canada paused distribution of the drug for now as it investigates inspection concerns at a Maryland facility where the active ingredient was made.

How many vaccine doses do I get?

All vaccines except Johnson & Johnson’s require two doses, though even for double-dose drugs, research suggests the first shots may give fairly strong protection. This has led health agencies to focus on getting first shots to as many people as possible, then delaying boosters by up to four months. To see how many doses your province or territory has administered so far, check our vaccine tracker for the latest numbers.

The European Medicines Agency is investigating a number of reports of patients developing blood clots, some of them fatal, within about two weeks of getting the AstraZeneca vaccine.

The agency said late Tuesday it is still reviewing reports from EU members, but “currently remains of the view that the benefits of the AstraZeneca vaccine in preventing COVID-19, with its associated risk of hospitalization and death, outweigh the risks of side effects.”

Thrombosis Canada said last week evidence did not show a link between the vaccine and blood clots. AstraZeneca said Sunday a review of 17 million patient safety records following vaccination also did not show a link.

Canada vaccine tracker: How many COVID-19 doses have been administered so far?

COVID-19 news: Updates and essential resources about the pandemic

Many European countries have suspended the vaccine temporarily pending the review. That includes Germany and France, which initially stood by the vaccine after the first reports of blood clots.

Several of those countries are the same ones that earlier this month decided their initial advice not to give AstraZeneca to seniors was no longer sound, as new evidence on the widespread use of the vaccine on seniors showed it was quite effective.

That same evidence is what led NACI to change its advice as well. Its chair, Dr. Caroline Quach, said those studies weren’t available when NACI developed its first guidance.

Most provinces heeded the warning two weeks ago not to give AstraZeneca to seniors, prioritized for doses across Canada because of their higher risk from COVID-19.

Provincial health authorities must now decide whether they will adjust their plans. Ontario Premier Doug Ford expressed frustration with the frequent changes.

“I can’t begin to tell you the logistics behind it,” he said. “It just messes everything up.”

Provinces might have some leeway. Most of the first 500,000 doses of AstraZeneca delivered are already spoken for and more doses are not set to arrive in Canada until April.

Chief public health officer Dr. Theresa Tam said Tuesday the warning bells are sounding that a third wave of COVID-19 infections is hitting Canada.

“We’re watching, of course, that epidemic curve really carefully, because there is this upswing we’re seeing now,” she said.

Over the last week the average number of new cases per day was about 3,200, she said. That’s up from 3,052 daily cases between March 5 and 11, and up from about 2,900 a day between mid-February and early March.

The death counts, however, have continued to drop, with an average of about 31 deaths a day in the last week, down from 41 a day a week ago, 52 at the beginning of March, and more than 80 in mid-February.

Tam said it’s too soon to know if the death rate is falling because of vaccines, though she said provincial governments have reported the rates of COVID-19 among people over 80, who were in the first groups to get inoculated, are now below rates for other age groups.

“That suggests that the vaccines might have a good effect,” said Tam.

Canada vaccinated almost 125,000 people Monday, the highest one-day total so far. More than 3.2 million doses have been given to date, with 2.6 million Canadians receiving at least one dose.

Tam said the existence of more contagious variants of the novel coronavirus brings added pressure and urged Canadians to remain careful even as vaccinations ramp up.

“This is not the time to increase your contacts,” she said.

There are more than 3,400 confirmed cases of variants in Canada, more than 90 per cent the B.1.1.7 variant that first emerged in the United Kingdom, but Tam said they are just “the tip of the iceberg.” There are potentially at least hundreds more cases screened for one of the mutations common to all variants, that have not yet been fully screened to identify which one.

Ontario’s “science table” said Tuesday it believed almost half the new cases in that province are now variants.

Canada had some positive vaccine news Tuesday as Quebec-based Medicago announced it was beginning the Phase 3 trial of its vaccine here. It is the only Canadian company on the list of seven vaccines procured by the federal government, and the first Canadian-made vaccine to get to this stage.

Nathalie Landry, the executive vice president of scientific and medical affairs, said it is also enrolling people in the United States and up to nine other countries.

Landry said the hope is to report results by the summer, and approval by the fall. If that happens, she said, Medicago can deliver 20 million doses to Canada by the end of 2021.

Moderna also reported Tuesday it had begun dosing kids under 12 in a study of its vaccine. Currently only Pfizer is approved for use on kids as young as 16. Moderna, AstraZeneca and Johnson and Johnson are only approved for 18 years of age and older.

With files from Maan Alhmidi in Ottawa and Shawn Jeffords in Toronto.

Canada's top doctor Theresa Tam says there is a need to collect and analyze data on the new variants of the virus that causes COVID-19 to avoid new outbreaks. Tam says looking at the data coming from other countries is important but is not enough.

The Canadian Press

This story was produced with the financial assistance of the Facebook and Canadian Press News Fellowship.

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