Coronavirus vaccine will need high uptake for life to shift toward normal: officials

Canada still determining percentage of COVID-19 vaccinations needed to be effective on wider scale: Tam
Canada’s chief public health officer Dr. Theresa Tam on Tuesday said they are still trying to determine the percentage of the population that should get vaccinated in order for it to be effective on a wide scale, but the international consensus is the 50 per cent mark. She said clinical trials will likely help in better knowing that percentage level. But in terms of countries impacted the most where population immunity also appears quite low, coronavirus vaccine uptake will be important.

Canadians will need to roll up their sleeves and get vaccinated in large numbers to finally corral COVID-19 before life can return to a semblance of its pre-pandemic state, Canada’s top public health officers said Tuesday.

“Widespread vaccine uptake is the best shot Canadians have in regaining some of what we’ve lost and returning to things that we cherish — things like holding family and friends closely, having community events and living our lives without the fear of contracting the disease,” said Dr. Theresa Tam, the country’s chief medical officer.

Tam and her deputy, Dr. Howard Njoo, offered that assessment one day after the Trudeau government announced the latest instalment in its plan to pre-buy tens of millions of doses of potential vaccines, signing deals with two American firms.

READ MORE: Canada secures 2 new deals for possible COVID-19 vaccines

The newest deals will allow Canada to buy as many as 76 million doses of a vaccine candidate from Maryland-based biotech company Novavax, and up to 38 million doses of the vaccine being developed by Johnson & Johnson’s pharmaceutical company Janssen Inc.

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Last month, the government signed similar deals with U.S. companies Pfizer and Moderna that would give Canada access to up to 76 million more doses.

Canada inks deals to secure millions of coronavirus vaccine doses
Canada inks deals to secure millions of coronavirus vaccine doses

Njoo said it is not clear what percentage of Canadians will need to get vaccinated to achieve broad immunity but “the more Canadians that take advantage, the better.”

Tam suggested that the threshold for effective immunization is a moving target because understanding the science around COVID-19 is itself a work in progress.

READ MORE: Safety of COVID-19 vaccine concerning some Canadians, StatCan survey shows

For regulatory purposes, she said, that level has to be continuously evaluated.

“The international consensus is that we should at least look at around the 50 per cent vaccine efficacy mark,” said Tam, adding that there simply isn’t a “yes or no” answer.

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More will be known when the data from ongoing Phase 3 clinical trials become available, she said.

“It’s a matter of remaining open to the evidence and being flexible.”

Right now, there appears to be low immunity to the disease around the world, “so getting a high enough vaccine uptake is going to be quite important,” said Tam.

Njoo said a vaccine could be available sometime in 2021, perhaps as early as the spring.

“We’re very optimistic here in Canada and because there are number of vaccine candidates being evaluated,” said Njoo.

“There could be an effective and safe vaccine, perhaps in 2021. We don’t know exactly when. Perhaps in the spring, maybe a little bit later. But it’s a very good thing to stay optimistic.”

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