Canadians immunized against COVID-19 with the Oxford-AstraZeneca vaccine can visit the United States when new travel regulations come into play next month, but it's not yet clear whether those with mixed doses will make the cut.
The U.S. Centers for Disease Control and Prevention said Monday travellers will be able to fly to the States if they've received shots of vaccines approved or recognized for emergency use by the World Health Organization or the U.S. Food and Drug Administration.
It did not say whether that included people who had received a mixed-dose regimen of approved vaccines.
"CDC will release additional guidance and information as the travel requirements are finalized," said a statement from spokeswoman Jasmine Reed on Monday.
The agency began informing airlines of its decision last week, she added.
Evan Rachkovsky, a spokesman with theCanadian Snowbird Association, welcomed the decision but said members had concerns and questions about those who received two different doses of vaccines.
"You're talking about millions of Canadians who aren't going to be permitted entry into the U.S., based on the fact that they have two different vaccine doses," Rachkovsky said.
"We do remain hopeful that not only people with AstraZeneca, but travellers with the mixed doses as well, will be permitted entry into the U.S."
Last month, White House officials said international travellers would be allowed to visit beginning in November as long as they were fully vaccinated. They did not say which vaccines would meet that criteria.
The U.S. Food and Drug Administration has approved three COVID-19 vaccines, and AstraZeneca was not among them. It is, however, approved by the WHO. It also does not allow for mixing doses of Pfizer and Moderna.
More than 3.9 million Canadians have two different doses of Health Canada approved COVID-19 vaccines, not including Quebec, which does not categorize data by vaccine product.
Of those, approximately 1.6 million had a dose of the AstraZeneca formula followed by an mRNA vaccine, data from the Public Health Agency of Canada shows. It's not yet clear whether those who have received a mixed-dose regimen will meet the criteria.
The COVID-19 vaccines approved under the WHO's emergency use listing have only been assessed as single product regimens, meaning people receive the same vaccine for both shots.
But the agency's Strategic Advisory Group of Experts on Immunization recommends mRNA vaccines -- Pfizer-BioNTech or Moderna -- can be used as a second dose following a first one with AstraZeneca if a second shot of the same is not available.
Canada is one of only a few countries that opted to mix vaccine types for their first and second doses last summer.
-- with files from The Canadian Press and CTV News --