OTTAWA - More health experts and politicians are breaking with advice from the national immunization panel, and instead urging Canadians that the best vaccine for them is the first one they can get.

That includes chief public health officers in Alberta and New Brunswick, which have both now reported a death associated with rare blood clots in patients who had received the Oxford-AstraZeneca vaccine.

“While any death is tragic, it's important to remember that risk of dying or other severe outcomes (from COVID-19) remain far greater than the risks following the AstraZeneca vaccine,” said Dr. Deena Hinshaw, the chief medical officer of health in Alberta, on Tuesday.

The risk of vaccine-induced thrombotic thrombocytopenia, or VITT, is estimated to be anywhere from one in 100,000 to one in 250,000 after getting either the AstraZeneca or Johnson & Johnson vaccine. Canada has authorized the latter but hasn't started using it yet.

That risk prompted the National Advisory Committee on Immunization to tell Canadians who are at low risk of a COVID-19 infection or severe illness from it to consider turning down a shot of either AstraZeneca or J&J even if it means they have to wait longer to get a dose of Pfizer-BioNTech or Moderna.

Most Canadians won't have to make that choice. Pfizer and Moderna account for almost 90 per cent of the expected deliveries of vaccines in the next two months, with enough coming from both to get everyone a single dose before Canada Day.

They also account for three-quarters of the total doses purchased of the four vaccines Canada has authorized.

But still NACI's advice has caused anger and frustration among those who already got AstraZeneca, many of whom now have a lot of questions about whether they should get their second dose.

The advice also directly contradicts the push from federal and provincial health officials for months that Canadians should not go vaccine shopping.

Health Canada Chief Medical Adviser Dr. Supriya Sharma said Wednesday she still firmly believes the best vaccine is the first one you can get.

“You know, what I say is that if your life is in danger, and you need to call 911, to get help to save your life, it does not matter if that call is made on an iPhone or a Samsung or even a flip phone,” she said. “It does what it is supposed to do.”

She said she doesn't intend to minimize the seriousness of VITT but said it's very rare, it's treatable, and has to be placed in context with the very real risks of COVID-19.

She noted 56 Canadians died of COVID-19 on Tuesday alone.

Canadians who received AstraZeneca already should get the second dose, said Sharma. However there are also ongoing studies about mixing and matching vaccines, so new advice about getting a different vaccine for your second dose could be forthcoming.

Sharma said there is not a lot of information about the risk of VITT from a second dose because not many second doses have been given. She said in the United Kingdom, four cases of VITT were diagnosed in more than 4.4 million people who received a second dose.

Canada has vaccinated more than 1.7 million people with AstraZeneca and reported nine cases of VITT, including three fatal cases. A 54-year-old woman in Quebec died last month. On Tuesday, Alberta reported the death of a woman in her 50s and New Brunswick reported Wednesday that a woman in her 60s had died about nine days after receiving the vaccine.

New Brunswick chief medical health officer Dr. Jennifer Russell said the vaccine will continue to be monitored but the risks of COVID-19 for people over 55 are greater than the risks of the vaccine. Only people older than 55 are currently eligible in that province.

“A death like this is tragic but it is equally tragic to have a person become gravely ill from a virus from which they can be protected by receiving the vaccine,” she said.

Hinshaw said people 50 to 59 years old are 350 times more likely to die of COVID-19, and 1,500 times more likely to be hospitalized with it, than they are to get VITT after getting AstraZeneca.

Deputy Prime Minister Chrystia Freeland, who received AstraZeneca herself nine days ago, said she is very happy she got it and urges all Canadians to go get vaccinated as soon as they can.

“When it's your turn please go and get the first Health Canada-approved vaccine available to you,” she said.

Freeland is one of a growing number of prominent Canadian politicians among the 1.7 million Canadians vaccinated with AstraZeneca. Prime Minister Justin Trudeau, Conservative Leader Erin O'Toole, NDP Leader Jagmeet Singh, the premiers of Ontario, British Columbia and New Brunswick, and health ministers in Ontario and Quebec are all AstraZeneca recipients.

Singh said he understands that Canadians are confused by the various comments on the vaccines. But he said he is grateful he got the AstraZeneca vaccine, he does not regret it and urges all Canadians to get whatever vaccine they can, as soon as they can.

More than 13 million Canadians have received their first dose already and many provinces are moving to accelerate plans to immunize everyone, with deliveries of vaccines increasing this month.

They can now offer them to kids as young as 12, after Health Canada authorized the Pfizer-BioNTech vaccine for 12 to 15 year olds Wednesday. Sharma said Pfizer intends to apply for approval in kids as young as five by September.

Canada is the first country to approve a vaccine for kids under the age of 16.

This report by The Canadian Press was first published May 5, 2021.