COVID-19 infection almost inevitable for the unvaccinated, expert says

The prevalence of the highly contagious delta variant means unvaccinated Ottawans will almost certainly come down with COVID-19 at some point in the coming months, according to Dr. Doug Manuel.

Dr. Doug Manuel says cases will need to be spread out to avoid further restrictions

Dr. Doug Manuel, seen here in 2020, says COVID-19 infections among the unvaccinated must be spread out in order to keep hospitals from being overwhelmed and to avoid further restrictions. (Submitted by Doug Manuel)

The prevalence of the highly contagious delta variant means unvaccinated Ottawans will almost certainly come down with COVID-19 at some point, according to a modelling scientist.

The comments by Dr. Doug Manuel, a senior scientist with The Ottawa Hospital who tracks local COVID-19 numbers, come as Ottawa's recent daily case totals have hit highs not seen since late spring.

On Friday, public health officials reported 50 new COVID-19 cases, as well as the first death from the illness in two months.

The city's test positivity rate sits at 3.5 per cent, more than twice what it was two weeks ago.

More than 90 per cent of known active cases are in people younger than 60, while the risk of COVID-19 infection is roughly 14 times higher for unvaccinated people.

"Eventually we'll all be exposed to COVID. It's just so infectious. The question is at what rate," said Manuel in an interview with CBC News.

"People who aren't vaccinated will become infected, whether it's this fall, this spring, next summer. It will happen. But if we can stretch it out, then the health-care system won't be overwhelmed."

Hospitalizations could rise sharply

As of Friday, 81 per cent of Ottawa residents aged 12 and up had been fully vaccinated, while 87 per cent had received at least one shot.

Still, that leaves between 200,000 and 250,000 unvaccinated residents, Manuel said, and that means hospitals could still become overwhelmed if case numbers suddenly shoot up.

Even with vaccination rates in the 80 per cent range, hospitalization rates are still forecasted to hit the peaks of last year, Manuel said — although a few percentage points here and there could mean the difference between cancelling elective surgeries and actually seeing restrictions loosen.

Modelling released last week by Ontario's COVID-19 science advisory table suggested more than 85 per cent of the eligible population needs to be vaccinated to avoid a fall lockdown.

"For a lot of the models, we really need to [have vaccination rates] into the 90s ... to avoid a lot of pressure this fall," Manuel said.

Ottawa's wastewater data as of Wednesday, Sept. 9. The levels of COVID-19 in the wastewater remain relatively stable, Manuel said. (

Wastewater staying constant

For the moment, local hospitalization rates remain low, with only six residents being treated for COVID-19 in a local hospital as of Friday and only one in intensive care.

Another "somewhat reassuring" factor, Manuel noted, is that the levels of COVID-19 in Ottawa's wastewater have remained relatively constant, even as daily case totals creep up.

The viral load in the wastewater is now almost entirely made up of the delta variant, he added.

Manuel said modellers are also keeping a close eye on variants like mu, which has been dubbed the latest variant of interest by the World Health Organization.

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