'Everybody right now...should still wear their mask': Canada's top doctor expects resurgence of COVID-19 cases

Update on COVID-19 in Canada: Epidemiology and Preparedness (Public Health Agency of Canada)

Dr. Theresa Tam, Canada’s chief public health officer, said Canada is in a period of "transition" in the COVID-19 pandemic, with anticipated resurgences in COVID-19 cases this spring, fall and winter.

"Not unexpectedly, the associated increase in in-person activities, more transmissible BA.2 variant and waning immunity may have contributed to increases in transmission as reflected in recent trends in daily new case counts, laboratory positivity and other indicators of increased virus circulation," Dr. Tam said on Friday.

As of March 30, daily average case counts have increased by 28 per cent across Canada, which indicates "a resurgence is underway."

Update on COVID-19 in Canada: Epidemiology and Preparedness (Public Health Agency of Canada)
Update on COVID-19 in Canada: Epidemiology and Preparedness (Public Health Agency of Canada)

"Currently, declines in lagging indicators of severe illness are levelling off, as with disease activity indicators, these trends show considerable variability regionally and are likely to follow the rising trend of cases to some degree over the coming weeks," Dr. Tam said. "The impact on health systems, such as hospitalization, is likely to be lower, that’s not a guarantee in every area of the country because of the differences in vaccine coverage and in other parameters."

Everybody right now, I think, should still wear their mask and keep those layers of measures, no matter where you are in this country because even if you don't see a resurgence now, you’re probably going to in the next days or weeks, and that will help reduce transmission and make sure that the impact on the health system is lowered.Dr. Theresa Tam, Canada’s chief public health officer

Wastewater surveillance shows considerable variability between difference sites. For example, Dr. Tam highlighted that community wastewater data shows a rise in Ottawa, whiles sites in Saskatchewan show declining COVID-19 signals.

Update on COVID-19 in Canada: Epidemiology and Preparedness (Public Health Agency of Canada)
Update on COVID-19 in Canada: Epidemiology and Preparedness (Public Health Agency of Canada)

"From mid-February to mid-March, vaccinated people continued to be at lower risk of hospital admission than unvaccinated people, with a hospitalization rate that was four times lower among fully vaccinated people than among unvaccinated people and 10 times lower among fully vaccinated people with an additional dose, than among unvaccinated people," Dr. Tam said.

While Canada’s chief public health officer indicated that case data nationally is "more unstable," which contributed to a lack of concrete future case projections in the latest modelling information, the national data indicates that a "worst-case scenario," an immune evasive and severe variant of concern will emerge and spread quickly. This would require the reimplementation of personal protective measures, including mandated masking and capacity limits.

A "realistic scenario," according to the latest modelling data, would result in "intermittent waves" with ongoing COVID-19 transmission.

"New variants emerge, sometimes spread and can cause rise in cases and severe outcomes," the information reads.

"Intermittent waves and outbreaks occur, and may coincide with influenza and other respiratory virus outbreaks but levels of cases and severe outcomes are expected to be manageable for health systems without the need for restrictive public health measures."