An informal survey shows that at least one million doses of Canada鈥檚 COVID-19 vaccine supply have gone to waste.

The Canadian Press asked health ministries across the country to provide the number of doses that had to be disposed of because they had expired or for other reasons.

Not all were able to reply by deadline. Some jurisdictions 鈥� including Yukon, Northwest Territories, and Prince Edward Island 鈥� only provided the number of expired doses. Ontario refused to provide any information.

The survey suggests at least 1,016,669 doses have been rejected since vaccines first arrived last December. That鈥檚 about 2.6 per cent of the entire supply delivered to the provinces and territories that provided their numbers.

Unused doses vary wildly across Canada. Alberta reported disposing of 10 per cent of its doses; Nova Scotia 0.3 per cent.

Some waste is to be expected, but Canada should be striving for the lowest amount possible, said Dr. Ross Upshur of Toronto鈥檚 Dalla Lana School of Public Health and co-chair of the World Health Organization鈥檚 COVID-19 ethics working group.

It鈥檚 difficult to know if Canada is meeting that goal because of poor data-sharing and a lack of transparency, said Upshur.

鈥淪ome of that wastage might be from breaches of cold chain (some vaccines must be kept at low temperatures), but some could be not getting them into arms before the vaccine expires. It鈥檚 a complex, complex, complex issue,鈥� Upshur said.

Provinces gave various reasons for wasted doses. They included dropped vials or syringes, defective syringes or damaged vials, poor dose managementand expired doses. Many could not provide a full breakdown.

Without complete data it鈥檚 hard to know whether Canada鈥檚 vaccine supply is being managed effectively, said Upshur. For example, onlysome provinces could provide the number of doses that expired.

In those provinces and territories, about 0.45 per cent of their vaccines had to be tossed because of an expiry date 鈥� about 120,578 doses.

鈥淔rom a basic ethics principle, you want to be efficient 鈥� waste not want not,鈥� said Upshur. 鈥淏ut also we know from decades and decades of vaccine program delivery that wastage is a reality.

鈥淎 million doses sounds like a lot 鈥� but then you have to ask the questions of what were the factors when you break down (what) led to the wastage of the vaccines.鈥�

Provinces report information about wasted doses to the COVID-19 Immunization National Operations Centre, but the Public Health Agency of Canada would not release the information.

When asked whether Canada has set thresholds for maximum COVID-19 waste, a spokesperson for PHAC said it works closely with provinces and territories to minimize wastage.

鈥淥ver the course of the rollout, provinces and territories have taken great care to minimize wastage,鈥� the agency wrote in a statement Friday.

鈥淗owever, as the proportion of eligible Canadians vaccinated continues to increase and demand goes down, it is possible that some increased wastage will be observed due to multi-dose vial presentations, fewer opportunities for use, and limited shelf life of the product once punctured.鈥�

A spokesperson for Nunavut鈥檚 Department of Health explained that with smaller populations in some communities there are sometimes doses left over in vials that can鈥檛 be saved.

Alberta鈥檚 Ministry of Health said wastage has become unavoidable because fewer people are coming in for shots.

As provinces begin rolling out their booster programs to fend off new waves of COVID-19, vaccine eligibility could lead to more waste, said Dr. Leyla Asadi, an Edmonton-based infectious diseases doctor.

鈥淚f doses are being discarded because of a lack of eligibility or strict criteria, then that鈥檚 inappropriate, because we know globally there is a gross shortage of vaccines. Any dose wasted is really quite sad,鈥� Asadi said.

Alberta continues to have hundreds of thousands of doses stockpiled, she said, yet pharmacists she鈥檚 spoken to say they鈥檝e been told to discard doses rather than give boosters to non-eligible people. Asadi said provinces can prevent waste by offering booster shots to anyone 18 or older, similarly to what Manitoba has done.

鈥淚t鈥檚 a bizarre situation we are in, because there are people in Alberta and other provinces who want that third dose.鈥�

Adam Houston, who works on medical policy for M茅decins Sans Fronti猫res (Doctors Without Borders) said Canada鈥檚 vaccine waste is concerning when 47 per cent of the world鈥檚 eligible population 鈥� the majority in sub-Saharan Africa 鈥� has yet to receive a first dose.

Canada has a stockpile of 6.5 million doses and has donated 6.4 million doses to COVAX, an organization working to provide COVID-19 vaccines to low- and middle-income countries.

鈥淎 dose sitting in a freezer somewhere not going into anybody鈥檚 arm and ticking towards expiry, that鈥檚 not something we want to see at all,鈥� Houston said. 鈥淎n expired dose is the worst scenario in a pandemic where many people don鈥檛 have access to a first dose.

鈥淭hat certainly suggests Canada could be doing more in this regard.鈥�

鈥擬ickey Djuric and Laura Osman, The Canadian Press