Health Canada regulators agree with Pfizer and BioNTech that you can regularly get six doses out of each vial of their COVID-19 vaccine.
Health Canada’s chief medical adviser Dr. Supriya Sharma says Canada is amending the label on the vials in Canada, which previously indicated the vials contained five doses.
Now it will say there are six.
The change means Pfizer will fulfil its contract to ship four million doses to Canada by March by sending fewer vials.
Maj.-Gen. Dany Fortin, the military commander overseeing Ottawa’s vaccine distribution program, says next week Canada will get the same number of vials it was expecting, but instead of Pfizer saying those vials contained about 336,000 doses, they will count them as 400,000 doses.
Sharma says after an independent review of the data, the regulators decided “six full doses could be obtained reliably” and still leave additional vaccine in a vial.
Health Canada normally requires vaccine vials to contain a small amount of extra liquid to account for how much gets trapped in syringes when the vaccines are injected.
Pfizer’s vials typically contained about 2.25 ml of vaccine once the dilution solution is added. Each dose is only 0.3 ml, which means even at six doses, almost half a millilitre is left.
Medical professionals began noticing they had enough left for a sixth dose when the vaccine was first approved in December, but until today Health Canada’s advice was only to extract that dose if possible.
Getting the sixth dose requires the use of a syringe that traps less vaccine in the syringe after it is injected.
Health Canada has ordered 64 million of the syringes, and deliveries began last week. Procurement Minister Anita Anand says the deliveries will continue through May.
The syringes are being tested now to make sure they meet standards.
Sharma said Pfizer did its own testing with nine types of syringe and found it could reliably get six doses from a vial.
Sharma said she has heard sometimes people have even been able to get seven doses.
The label change requires the company to take reports on difficulties getting that sixth dose.
Health Canada is also providing webinar training this week to guide medical professionals in how to get the sixth dose.
Canada’s contract with Pfizer and BioNTech is to buy 40 million doses this year, with four million to be shipped by the end of March, and most of the rest before the end of September.
The United States, Europe and the World Health Organization all made the dose change last month.