There are more COVID-19 cases in N.L. than reported, but modeller doesn't expect further spikes
15-20%of province has likely caught COVID, Fitzgerald says
A COVID-19 modeller in Newfoundland and Labrador says more cases are spreading across the province than reported but the removal of public health measures next week likely won't cause a dramatic spike in new infections.
Amy Hurford, a mathematical biologist at Memorial University, says she has worked to estimate the true number of COVID-19 positive people in Newfoundland and Labrador, as the number reported by public health officials often doesn't paint the full picture of spread in the province.
COVID-19 testing criteria has changed in recent months, and positive test results found through rapid antigen tests don't appear in public figures.
Hurford conducted her own research on the number of positive cases in January, asking parents to supply the test results of children returning to school in the winter.
"Based on the percentage of reported positives, we estimated that … for every one reported case, [there were] about 5.4 unreported cases," Hurford told CBC News on Tuesday.
"That's likely an overestimate, because if you think of that situation you've got kids in the same household or kids in the same school, so you sort of get an inflated number of positives that way relative to the number reported by the province."
Hurford also curated statistics using the positivity rate of reported tests, estimating a ratio of about four positive cases for every one reported case. She said that could also be an overestimate, as the data suggests a bias that only people who know or suspect they are positive for COVID-19 take a PCR test.
"I think we know there's more COVID than gets reported. Not everyone who has COVID goes for testing now either," she said. "With a lot of rapid tests now, potentially there's less demand for PCR testing, which can take a while to get the results back."
The idea that COVID is more prevalent than the reported numbers isn't new to Public Health, according to Chief Medical Officer of Health Dr. Janice Fitzgerald, who said during a February briefing she believed there were two to three times as many cases than reported at the time.
On Wednesday, Fitzgerald estimated that between 15 and 20 per cent of people in Newfoundland and Labrador have caught the virus at some point over the course of the pandemic.
Despite a rise in cases in recent weeks, the province will still remove all public health restrictions on Monday.
Even more cases are expected as the province reopens, said Hurford, but she doesn't expect to see them rise as quickly as in previous waves.
"I think the rate that cases are rising in terms of the doubling time and the steepness is slower, which I think is suggesting that the booster shots are working to slow infection," Hurford said.
"If we drop some more measures we'll maybe see a bit more quick exponential growth, but it won't be as noticeable as if we were in a situation where we were having a decline … and it got reversed to an increase. I think the additional amount of increase that we'll see probably won't be that evident in the data."