The percentage of the Canadian population that needs to be vaccinated in order to reach widespread immunity against the coronavirus is unknown, according to Canada’s chief public health officer Dr. Theresa Tam.
Speaking as a media conference Friday, Tam was asked what entails a “successful vaccine campaign,” in order to determine when the population reaches herd immunity.
“Nobody actually knows the level of vaccine coverage to achieve community immunity or herd immunity,” Tam explained. “We have an assumption that you will probably need 60 to 70 per cent of people to be vaccinated. But we don’t know that forsure … that’s modelling. Lots of these calculations are being done but bottom line is that we actually don’t know.”
The end goal, Tam added, is to vaccinate as many Canadian as quickly as possible.
According to the World Health Organization (WHO), herd immunity is when a population can be protected from a certain virus, like COVID-19, if a threshold of vaccination is reached. It’s achieved by protecting people from a virus, not by exposing them to it, the WHO added.
However, the percentage of people needed to be vaccinated in order to create herd immunity depends on the disease.
For example, herd immunity against measles requires about 95 per cent of a population to be vaccinated and for polio, the threshold is about 80 per cent, the WHO stated.
Tam previously told Global News in November that Canada is still nowhere near herd immunity with the coronavirus.
“We’re only at a few percentage points in terms of the immunity in our population. That leaves over 90 per cent of the population, or 95 per cent of the population still vulnerable,” Tam said.
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