Early trials for Pfizer COVID-19 vaccine offers hope, but experts say logistical challenges remain

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While experts welcome Pfizer's progress in developing a COVID-19 vaccine, somecaution that Canada still faces a massive logistical challengeto distribute it and immunize its population of more than 37 million people.

"This is the greatest public health distribution in Canadian history," said Rebecca McKillican, CEO of drug wholesaler McKesson Canada.

McKesson Canada has been pitching itself as a potential partner to the federal government to distribute the vaccine. It also recently published a report on the supply chain challenges that face a COVID-19 vaccine rollout.

The flu vaccine, McKillican explained, is usually distributed to about 30 per cent of the Canadian population, totalling 10 to 15 million doses.

Because Pfizer's vaccine currently requires two doses, "we're looking, now, at 75 million doses [to vaccinate], frankly, every Canadian," she told The Current's Matt Galloway.

"There's a lot of things and a lot of unknowns ... that need to be determined in order to effectively distribute and inoculate all Canadians."

Pfizer said Monday that its new vaccine may be 90 per cent effective at preventing COVID-19, but provided little data about its research, and cautioned that the initial protection rate might change by the time the study ends.

Prime Minister Justin Trudeau said the announcement was an "encouraging" development. Pfizer's vaccine is one of seven that Canada has pre-ordered, numbering in the millions of doses. Other partnered companies include Moderna, Novavax and Janssen, a subsidiary of Johnson & Johnson.

On Tuesday, Canadian drug developer Medicago said it received promising Phase 1 clinical trial results for its plant-derived COVID-19 vaccine.

Who gets it first?

Dr. Caroline Quach, a pediatric infectious disease specialist and chair of Canada's National Advisory Committee on Immunization (NACI), said the federal government "has already secured all the necessary syringes and needles, apparently to vaccinate all Canadians."

The most important question once a vaccine has been approved, she said, is who should get it first. And it will take more information than Pfizer has thus far released to determine that, she explained.

An independent monitoring board looked at 94 infections recorded so far during the trial to see which occurred among those who received the real shot versus those who received a dummy shot or placebo.

It did not say how many infections occurred in each group, and participants were only tested if they developed symptoms meaning it's possible some participants could have become asymptomatic carriers.

The analysis so far looked for cases of COVID-19 seven days after the second dose. Pfizer has now said it will also look for cases 14 days after the second dose.

"We don't know what type of populations in terms of other chronic conditions, racial diversity, age groups [that these positive cases occurred]. So who got infected in both the vaccinated and the unvaccinated group? We don't have any data yet on safety," she said.

"Once we know more [about the vaccine], if we decide to start with health-care workers, it's going to be a completely different strategy than if we start by vaccinating the elderly in long-term care facilities, for instance," she said.

In the meantime, provinces will have to work on "two or three plans in parallel, just in case."

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Prime Minister Justin Trudeau spoke with reporters, including the CBC's Tom Parry, during a media briefing on Monday.

According to Helen Branswell, an infectious disease and global health reporter with STAT a news outlet covering health sciences the Pfizer vaccine currently has to be stored at -70 C to maintain stability. Pfizer has built special freezers to keep it cold, but it can only be opened once or twice a day.

"It's likely that it's going to be most useful in, like, large medical centres where, you know, there are a lot of health-care workers, for instance, to be vaccinated and where they probably have ultra-cold storage fridges," she said.

"I'm told the company is working to try to, you know, improve its stability at fridge temperature so that it could get rid of this requirement. But for the moment, it is going to be a limiting factor in terms of where the vaccine could be used."

'It's going to be a lot of work'

When asked about whether she had worries about people who are vaccine-hesitant, Quach told Galloway she prefers a strategy of education and transparency over mandatory vaccination.

"If we are transparent with the data, if we inform the population, at least those who are just, you know, wondering if it's safe and if we're cutting corners, will see that we are not ... that should be helpful," she said.

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"We just need to have as many sticks in the fire as possible," says infectious disease specialist Dr. Isaac Bogoch.

Despite the challenges that lay ahead, Quach is confident that Canada is well-equipped to figure them out and eventually protect the population from the coronavirus that has already killedthousandsand reshaped our lives.

"I think it's going to be a lot of work, but I think we can do it. And, anyway, we have to do it."

Written by Jonathan Ore with files from CBC News. Produced by Julie Crysler and Rachel Levy-McLaughlin.