Science community divided on when to lift COVID-19 public health restrictions
Herd immunity should now be 95% of residents with 3 doses, says member of Ontario science table
Ontario has announced its plan to ease public health restrictions by the end of March 2022, but that decision continues to be a topic of debate among the science community.
On Friday, the province announced it will begin lifting capacity limits in certain venues Monday before removing all COVID-19 health measures — provided key indicators don't rise significantly — by the end of March 2022.
Dr. Doug Manuel, a senior scientist with The Ottawa Hospital and member of the Ontario COVID-19 Science Advisory Table, argues COVID-19 is here to stay, so it's still difficult to determine when the province should lift restrictions.
"It's just too infectious ... so even if we got rid of it all from humans it's still going to come back now from multiple animal reservoirs," said Manuel.
Manuel said lifting restrictions would signal the transition from a pandemic to considering the virus endemic — where COVID-19 is like the seasonal flu that tends to be most prevalent during the colder months.
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Herd immunity now 95% with 3 doses: Manuel
Manuel said the science table has talked about late spring as a possible transition time, but it will also depend on the number of cases, hospitalization rates, community immunity, and who in the community is vaccinated.
Instead of herd immunity being reached with 85 per cent of residents with two doses of a COVID-19 vaccine, he says the science table now believes that mark should be when 95 per cent of residents have three doses.
Manuel also says there is concern a transition done too quickly could cause cases of COVID to rise, which has been seen in some western European countries and Alberta earlier this summer.
"People who aren't vaccinated will still get exposed and that first exposure is going to be a doozy for many, meaning that they may get hospitalized or die," he said.
New variant could throw plan off course
Dr. Gerald Evans, chair of the division of infectious diseases at Queen's University, remains more cautious as he looks at the pandemic situation around the world. He believes the transition to an endemic situation worldwide could still be more than a year away.
"Maybe by 2023, with continued vaccine rollout, that may be the point where we get into endemicity," said Evans. "But it's very possible that even next year in 2022 the [World Health Organization] may declare that the pandemic is over."
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For that to happen, Evans says case numbers and worldwide vaccination rates will dictate the call. One aspect that may throw models into disarray, he said, is a variant of concern that takes over from delta — something that hasn't happened this fall.
"If there were to be a variant that was even more transmissible than delta ... or if there's a variant that somehow is able to escape the protection that the vaccines provide ... that could change the whole story and we would be back to trying to revaccinate the population."
with files from Adrian Harewood