While the 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.

Jean-Paul Soucy, a PhD student in epidemiology at Dalla Lana, agrees that once we reach the point where a majority of the population is vaccinated then governments can relax restrictions. “The ability for the virus to spread will be … much less.”

“Herd immunity is going to have a huge effect,” Soucy said. While we won’t be able to completely forget about the virus, “its control of our lives will be much less at that point.”

Soucy said he believes that by the end of summer, “we should be in an excellent position to start moving past (heightened public health measures).”

Lee says she hoped that by the end of 2021, we could be back to some semblance of pre-COVID normalcy. However, she cautions that we don’t yet know how long the vaccine will offer immunity from the virus.

“We don’t know how frequently, for example, we may need to be revaccinated,” she said. “I think we will still be looking at maintaining some distancing and masking for some time ahead.”

Jenna Moon is a breaking news reporter for the Star and is based in Toronto. Follow her on Twitter: