Experts fear true number of COVID-19 cases in B.C. could be higher as province hits testing capacity

Experts are saying B.C. could be undercounting COVID-19 cases as the province hits its testing capacity amid its worst surge of infections yet.

Provincial Health Officer Dr. Bonnie Henry said Friday that the province had reached maximum capacity on testing and contact tracing.

She added that with hours-long lines at testing sites the province was "triaging" tests by providing rapid antigen tests to those at lesser risk, saving the more accurate polymerase chain reaction (PCR) tests for those at higher risk.

"If you are younger and don't have underlying risk factors, particularly if you're vaccinated, then rapid testing may be the most efficient way for you to get what you need," Henry said Friday.

She said PCR testing should be available for those most at risk, as well as health-care workers who need negative tests to work. The people most at risk, according to Henry, include older people, immunocompromised people, and young children.

The province conducted 21,123 PCR tests on Dec. 23, the most ever, and identified 2,414 cases on Christmas Eve, a record number driven by the more infectious Omicron variant.

All those cases came from positive PCR tests, the province later told CBC News. With positive rapid tests not factored into daily case numbers — and a ceiling of around 20,000 daily PCR tests — experts say future pandemic analysis will be murkier.

"[Hitting the testing capacity] will make it harder to interpret the data," said Caroline Colijn, a mathematician and Canada 150 research chair at Simon Fraser University. 

"We won't know how many tests we would have done if we had not been running up against capacity."

Colijn is part of an independent modelling group that predicted record hospitalizations over the next few weeks.

In a Thursday report, the modelling group also noted the importance of counting cases derived from rapid antigen tests.

"As self-administered rapid antigen tests become more common, we will lack information about these cases unless an effort is made to log and publicly report them," the report reads. 

"Once testing and hospitals reach capacity, it will be challenging to track the growth in infection rates."

In a statement, the Ministry of Health said there are no requirements for anyone who tests positive from a rapid test to self-report their test.

"We have an online system for them to do that in use at Vancouver Coastal Health and that is being expanded provincially," a Health Ministry spokesperson said. 

"We have always known that our surveillance does not capture every case. That is why we have several streams of surveillance, and we will be focusing more on surveillance for severe illness."

Sarah Otto, another member of the modelling group and a professor at the University of B.C., said the province's fifth wave is only going to get worse due to how fast Omicron is spreading.

"With the projections, we're seeing skyrocketing numbers of cases … three, three-and-a-half-day doubling times," she told Gloria Macarenko, host of CBC's On The Coast, on Thursday. 

"No matter which way you cut it, it is looking really, really bad for the beginning of January."