Manitobans who got 1st dose of AstraZeneca-Oxford vaccine can get Pfizer or Moderna for 2nd

Manitobans who got a first dose of the AstraZeneca-Oxford vaccine can receive a second dose of either the Pfizer-BioNTech or Moderna vaccine if they meet provincial eligibility requirements, the province says.

People who got 1st dose of any COVID-19 vaccine on or before April 8 can now book 2nd dose

Manitobans who received a first dose of the AstraZeneca-Oxford vaccine can get an mRNA shot for their second dose. (Francis Ferland/CBC)

Manitobans who got a first dose of the AstraZeneca-Oxford COVID-19 vaccine can receive a second dose of either the Pfizer-BioNTech or Moderna vaccine if they meet provincial eligibility requirements, the province says.

The minimum time that must pass before people who got AstraZeneca get a second dose is 28 days, and for those who aren't in a higher risk category, eight weeks is recommended.

As of Monday, anyone who received a first dose of any COVID-19 vaccine on or before April 8 can book a second-dose appointment.

Those who got their first shot on or before April 13 will be able to book a second-dose appointment starting Tuesday at 11:45 a.m.

Canadian health officials have been reviewing research on mixing various COVID-19 shots for several weeks.

WATCH | Dr. Joss Reimer on mixing shots:

Manitobans who got AstraZeneca can have Pfizer or Moderna for 2nd shot

4 months ago
Manitobans who received a first dose of the AstraZeneca-Oxford COVID-19 vaccine can get a second dose of either Pfizer-BioNTech or Moderna if they meet eligibility requirements, the province says. 1:17

Manitoba was waiting for the results of a U.K. study, which were due to be released this month, before making a decision on mixing vaccines, but the results of that study are now expected a month later, said Dr. Joss Reimer, the medical lead for Manitoba's vaccine implementation task force.

"The good news is that a Spanish study has been released that showed that people who received a second dose of an mRNA vaccine [such as Moderna or Pfizer-BioNTech] after AstraZeneca had a good immune response," she said.

This lines up with what scientists see with other vaccines.

"We've seen that changing products in between doses for almost every other vaccine still results in good effectiveness, and ultimately that's what we're after: the effectiveness of the vaccine in preventing the spread and the severity of a COVID infection," Reimer said.

WATCH | Dr. Joss Reimer on increasing vaccine uptake:

Dr. Joss Reimer on what Manitoba's COVID-19 vaccine task force must do to increase uptake

4 months ago
Dr. Joss Reimer, medical lead of Manitoba's COVID-19 vaccine task force, said Monday the province is working to improve uptake. The task force is tackling vaccine hesitancy by working with community leaders, she said, and plans to improve vaccine access for those who want a shot but face barriers to getting one. 2:29

The Spanish study mixed Pfizer with AstraZeneca, but Reimer says Pfizer and Moderna are essentially the same vaccine with different brands.

"We expect that whether you got Moderna or Pfizer after AstraZeneca, you would get an equivalent immune response," she said.

"We want people to get those second doses as soon as they hit that eight-week mark and don't want them to worry about vaccine shopping."

Reimer reiterated that people who got AstraZeneca did the right thing, and that one or two doses of that vaccine are better than not being immunized at all.

There are some rare cases of blood clots that have been reported after people got the AstraZeneca vaccine, but now that there's a large supply of the Pfizer and Moderna vaccines, the task force wants to prioritize those doses.

"We want to move to something that's even lower risk," Reimer said.

All Indigenous people in Manitoba and those with specific health conditions are also eligible to book a second dose, as long as they meet the minimum time interval between doses.

Second province to mix

Manitoba is the second province in Canada to recommend an mRNA vaccine for the second dose.

Quebec doesn't recommend it — at least not yet — but says people who have had AstraZeneca for the first can choose to have either Pfizer or Moderna for the next.

Reimer says many European countries have also opted to mix following the results of the Spanish study.

Canada's National Advisory Committee on Immunizations hasn't yet endorsed the move, but Dr. Zhou Xing, a professor at McMaster University's Immunology Research Centre believes it's a good one.

"This will provide with a lot more flexibility depending on the vaccine supplies," he said.

"All indications seem to suggest that it is safe, except perhaps that the mild symptoms are more frequent than when you use two same doses of the vaccine."

A file photo of Dr. Isaac Bogoch, an infectious disease specialist in Toronto. He's glad that Manitoba made the move to mix vaccines. (Craig Chivers/CBC)

The decision is especially important for those who have mixed feeling about AstraZeneca, says Toronto infectious diseases physician Dr. Isaac Bogoch.

"There's some very, for lack of a better word, polarizing opinions on AstraZeneca. Some people want to get a second dose of that vaccine, other people don't," he said.

"By enabling people to make informed decisions and giving them the opportunity to either get a second dose of AstraZeneca or a second dose of an mRNA vaccine, I think we'll do a lot of good."

All Manitobans 12 and up have been eligible for a first dose appointment since May 14.

As of Monday, a total of 852,094 vaccinations have been administered in the province. Just over 61 per cent of people 12 and up have received at least one dose.

You can book appointments on the province's website or by calling 1-844-626-8222.

WATCH | Full news conference on COVID-19 | May 31, 2021:

Manitoba government daily briefing on coronavirus: May, 31

4 months ago
Provincial officials give update on COVID-19 outbreak: Monday, May 31, 2021. 45:37


Rachel Bergen is a journalist for CBC Manitoba and previously reported for CBC Saskatoon. Find her on Twitter at @r_bergen or email her at


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