'The pandemic is not over': Experts expect a surge in COVID cases this fall

Higher COVID-19 levels seen in Ottawa in the past month are expected to continue to rise through the fall, public health experts warn. 

Coronavirus levels in Ottawa's wastewater have been increasing since the end of July, and the city saw an average of 28 patients in hospital because of active COVID-19 cases during the week of Aug. 21.

This number has come down since the previous week, but is much higher than the single digit averages reported in July. 

The highly mutated new variant BA.2.86 was also detected in Canada for the first time on Tuesday.

Ottawa's medical officer of health Vera Etches confirmed Thursday these trends will increase in the coming months, but said it's not yet clear that subvariants are driving the surge. 

"It's more that we're in close contact with each other," she said.

"Regardless of the variant, there are things we can do to decrease spread of respiratory illness," she said, emphasizing masking, staying up to date with vaccinations, and staying home when sick as effective practices to reduce spread going into the fall. 

Etches also noted COVID-19 will be one of several respiratory illnesses that will be circulating, along with influenza and RSV.

Rising virus levels in wastewater

The latest data from Ottawa's wastewater monitoring program shows a steady increase in COVID-19 virus levels since the end of July, and forecasts this upward trend will continue into the fall.

"Based on that I think it's a foregone conclusion we're in a late summer, early fall wave, and that this wave will continue for at least the next couple of months," said Tyson Graber, co-lead investigator of the wastewater monitoring project.

"Unsurprisingly at this point, that [increase] is followed by an increase in hospitalizations, which we've seen now in Ottawa over the last couple of weeks."

Graber said the wastewater samples contain several different variants but that Omicron subvariant EG.5 has been out-competing the others since the beginning of August.

This subvariant has been circulating in Canada since at least May, according to the Public Health Agency of Canada, and experts say it is responsible for the surge in cases that has been reported in the last month. 

Graber said the wastewater data indicates the uptick in COVID-19 levels he's seeing right now will likely continue well into the fall.

"Based on the wastewater data alone, looking at Ottawa, we probably won't be done with this wave until at least October or November, based on the current trajectory," he said.

Graber determines how long a wave will last based on a trajectory extended from the current trend.

"In the past, this hill has been steeper," he explained. "Right now, the trajectory is a bit of a less steep hill, meaning that the entire wave will be a little bit longer than in previous waves."

Graber said a handful of variables that could change this forecasted trajectory, including the coming return to school, an increase in indoor activities, waning immunity, and new variants coming through the door.

Subvariant BA.2.86 has not yet been detected in Ottawa's wastewater, but Graber expects it will show up within the next month.

"The pandemic is not over, but there are measures available to reduce both personal risk and community risk," he said.