Pfizer-BioNTech and Moderna are the only vaccines so far approved for use in Canada.
Both of those vaccine suppliers have significantly slowed deliveries to Canada after a combination of manufacturing delays and demands from Europe, where Canada procures its doses, to restrict vaccine exports subject to EU approval.
Canada did not attempt to procure any vaccine doses from the US after the Trump administration indicated it would not allow any vaccines to be exported.
Provinces in Canada, who are responsible for vaccine distribution, are growing frustrated as mass vaccination sites are ready, but in many cases sit "empty" awaiting vaccine doses.
"They have the capacity of several thousand each per day and the possibility to ramp up past that so all of us are a little disappointed, a little frustrated, and chomping at the bit to do more and get the vaccines to us," said retired general Rick Hillier, now leading Ontario's vaccine task force.
He added that he has lost confidence in the Pfizer supply chain as doses that were promised to Canada were not delivered.