Health Canada has approved a label change requested by Pfizer that will now allow for one extra dose to be extracted from each of the company’s COVID-19 vaccine vials.
The labelling change means that six shots, not five, can be squeezed out of each vial. As a result Pfizer can also ship fewer vials to meet its contractual obligations which are based on the number of ‘doses’.
However “in order to extract a sixth dose reliably and consistently, a specialized syringe should be used,” said Dr. Supriya Sharma, Health Canada’s chief medical adviser.
The federal government will be launching a series of “webinars” to train health care professionals on how to use the new syringes, added Dr. Howard Njoo, Canada’s deputy chief public health officer.
“I think the real live issue right now is to ensure our provinces and territories can reliably and consistently get six doses out of each vial,” Njoo said.
Health Canada’s move follows a similar label change by the European Medicines Agency and the U.S. Food and Drug Administration (FDA) late last year.
According to health officials, each Pfizer vial contains 0.25 mL of product, to which saline is added as a diluting agent to obtain 2.25 mL of vaccine solution. Each patient receives a 0.30 mL dose which means there is enough product in a vial to comfortably cover six shots and still have a “buffer,” and to account for possible wastage.
Pfizer will be required to assist in Canada’s rollout of this change, including informing Health Canada quarterly of any issues reported from vaccine sites having issues extracting a sixth dose.
According to Sharma there have been anecdotal reports of some jurisdictions squeezing a seventh shot from these vials.
Canada has a contract with Pfizer to receive 40 million doses of the vaccine, four million of which are to be delivered by the end of March. After weeks of shortages, there will be significant increases in week’s shipment and those in the weeks ahead. Moreover by counting the sixth dose, the number of doses per shipment will increase considerably.
“While there is a change in doses contained in each vial, the country’s overall allotment from the manufacturer remains the same,” said Major-General Dany Fortin, the military commander leading vaccine logistics at the Public Health Agency of Canada.