As COVID-19 infections in Ontario hit record highs Thursday, some health experts say the true number of new cases is likely much higher than is being reported, raising concerns of a homegrown variant developing.
Ontario hit a record 5,790 reported cases Thursday and Toronto followed suit with its highest-ever daily count of 2,309, but experts say these numbers no longer tell the full story.
They say the actual number of infections has likely become unknowable and far beyond what are reported in the daily case counts.
The province’s PCR lab test network, which is how case counts get reported, is strained, unable to test everyone who may have the virus.
“What we’re seeing is just the surface,” said Dr. Saverio Stranges, chair of the epidemiology and biostatistics department at Western University. “Many public health scientists, in many countries, are suggesting that we should really focus on hospitalizations now.”
In Toronto, daily hospitalizations have actually dropped. Last week’s average was 2.7, down from 4.6 the week before. The pandemic peak was 93 in April.
But Stranges warned that focusing only on hospitalizations could create a false sense of security.
Most of the population is vaccinated, and therefore unlikely to be hospitalized if they contract Omicron. But a small, yet significant, portion is still extremely vulnerable to the worst of the virus. Case counts provide an idea of their relative risk in coming into contact with other people. If ignored, they could end up in more danger than they know.
“A segment of the population — the most fragile, people with co-morbidities, older adults — they have severe ramifications from infection,” Stranges said. “It’s a tradeoff. We can’t rely on case counts as much, but we still need to look at them to inform our public health policies.”
Dr. Eileen de Villa, Toronto’s public health chief, said that the seven-day average for hospitalizations in city had dropped, but that there has been a slow rise in recent days “that will take a little more time to be reflected in that seven-day moving average,” she said. “I think you will see it start to rise.”
In an interview Thursday, De Villa said there is still “conversation and careful observation and monitoring” of all COVID-19 metrics, including case counts.
“Case counts are still being observed but increasingly we are looking at things like hospitalizations, ICU, per cent positivity and reproductive numbers,” said de Villa. “Based on what we’re seeing, we’ll be making recommendations (to the province) about what does the evidence suggest would help us.”
The more people infected with the virus, the more opportunity for it to mutate, said Omar Khan, a U of T expert on molecular engineering.
High case counts are “directly linked to viral evolution,” he said. “If we’re increasing replication numbers, we’re always increasing the odds of mutations and evolution of a new variant.
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“This rapid evolution is what got us Omicron and Delta and Beta and Alpha.”
Khan pointed to kids aged 5 to 11 as an example of a population still not fully protected.
“There’s a huge amount of people who are actually partially vaccinated, not because they are anti-vaxxers but just because they literally couldn’t get it,” said Khan.
De Villa said concerns over another variant developing is a major reason Toronto is asking residents to limit contacts.
“The more transmission there is, the more opportunity for the creation of a new variant — that’s always been a new concern,” she said. “It could be here or in the United States or western Europe where they are also seeing rapid growth.”
Evolution in virus is making it harder for our current tests to detect variants, Khan said.
“Evolution, if it continues to change the virus enough, our diagnostic tools have to be updated and it takes time to develop new ones,” he said.
Another indicator of risk is the test positivity rate — the amount of PCR tests per day that return positive results. On Thursday, test positivity in the province hit a staggering 16 per cent.
“In Europe, it’s been around four to five per cent,” said Stranges. “It’s likely that it’s even higher here, because it’s likely we’re missing many cases.”
Stranges said if the positivity rate stays this high or grows, it’s possible Ontario will need to implement more stringent public health measures.
“It’ll also come down to hospital capacity, that always drives political decisions,” he said. “And the potential impact of the virus on essential workers. That is certainly a concern, and that concern could push for more stringent measures.”
When asked Tuesday if people should still be focused on case counts, Dr. Kieran Moore, Ontario’s public health chief, said the province will begin increasingly focusing on hospitalizations and ICU admissions, with the knowledge it is under-testing and not capturing all the exponential case growth happening.
Ontario is looking for when, or if, Omicron starts impacting hospitalization and ICU rates “as a signal that we’re going to have to take potential extra precautions.”
Ben Cohen is a Toronto-based staff reporter for the Star. Follow him on Twitter: @bcohenn
David Rider is the Star’s City Hall bureau chief and a reporter covering city hall and municipal politics. Follow him on Twitter: @dmrider
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