While the COVID-19 vaccine will alleviate much of the need for physical distancing and masking long-term, it won’t immediately end public health measures, epidemiologists say.
Herd immunity, which refers to a large proportion of the community being immune to contracting the virus via vaccination, has to hit about 70 per cent in order for COVID-19 to be manageable, said Dr. Robyn Lee, an infectious disease expert and adjunct professor at the Dalla Lana School of Public Health.
Until we reach that threshold, public health measures need to continue.
“It’s going to take some time. And as the vaccine becomes available, we obviously have priority groups that need to be vaccinated first,” Lee said. “It’s going to be a number of months before the whole Canadian population has received a vaccine.”
The vaccine protects against symptomatic COVID-19, she said. Still unknown, however, is whether the vaccine will stop transmission entirely. At this point, it’s unclear if vaccinated people could be asymptomatic and still spread the virus to others.
“We don’t actually know whether (the vaccines) prevent somebody from becoming infected and then spreading it forward,” Lee said. What that means is that if there is a large amount of the population that isn’t yet vaccinated, they’re still at risk of potentially contracting the virus from vaccinated people.
“The key issue is that if people are vaccinated, and they can still spread it, then that’s a risk to the people who aren’t vaccinated,” she said.
While masking and physical distancing are necessary while the community builds herd immunity, this won’t last forever. As more people are vaccinated, restrictions can be reduced as potential outbreaks become easier to manage, Lee said.