B.C.'s unknown COVID-19 case count makes 6th wave, long-term effects unpredictable: expert

A medical worker holds a rapid COVID-19 test showing a positive result, at a testing site set up by the city department of health outside the Pino Suarez subway station, in central Mexico City, Friday, Dec. 4, 2020. (AP / Rebecca Blackwell)

Not knowing how many people in B.C. are or have recently been infected with COVID-19 makes predicting how the sixth wave of the pandemic will unfold "very uncertain," according to an expert with an independent modelling group.

While the Ministry of Health has continued to report on case numbers, those figures only capture "lab-confirmed, lab-probable and epi-linked cases" detected through PCR testing. Eligibility for this testing has been limited since capacity was overwhelmed in December of 2021.

Dr. Caroline Colijn, Canada 150 research chair in mathematics for evolution, infection and public health at Simon Fraser University, says not knowing how prevalent the virus was during the last wave makes it extremely difficult to understand what might come next.

"We don't know how many people just had COVID in the Omicron wave and that's because we really dramatically changed testing at exactly the same time as the Omicron wave happened," she says, adding knowing who was infected and when is important for tracking things like immunity and susceptibility to reinfection with the now-circulating BA.2 variant.

"Depending on the number of infections there are, and on the waning of boosters in our most vulnerable age groups and people, it's hard to predict – even if you knew how many infections there were going to be – what's the burden on the health-care system."

While rapid antigen tests are now widely available to all adults, there is no record being kept or report available indicating the results of those tests. The B.C. Centre for Disease Control recently discontinued its online results reporting option.

On Thursday, the province released its first weekly report on COVID-19. It showed an increase in hospitalizations and deaths, and a slight decrease in the number of people in intensive care.

But Coljin says only measuring these severe outcomes means there's no way to understand how the circulation of the BA.2 variant and the lifting of restrictions are impacting transmission.

"It may be that we're getting infections and we don't see hospitalizations because immunity is so strong. On the other hand, that's really hard to know without knowing how many people got COVID in the first Omicron wave," she says.

"We do know that the BA.2 sub-variant is rising in Canada, is predominant. We know that it's more infectious. We know that we've removed protective measures, like mask mandates, and so on, and we know there's going to be a change in behavior."

While there are some ways to get a sense of how much COVID is currently circulating, like wastewater monitoring and antibody testing among blood donors – Coljin says no data that is currently available gives modellers or the public access to the same information that widespread testing would.

"We really lose that ability to detect what's happening right now," she says.

"It's fundamental to knowing what's going to happen with the pandemic and how immunity looks and how at risk we are of a new variant, that is really important. What are infections going to look like? What's the fall wave going to look like? What are hospitalizations going to look like? The fundamental driver of all of that is infection."

Further, she notes that even if infection in and of itself is not severe for a majority of people, there are a host of other consequences to widespread transmission.

"We will have societal impacts of this pandemic that are not hospitalizations, ICU, and death. Those are things we've counted and we've been good at counting them and we've focused on them. But there are other things that this virus can do to people that aren't hospitalization, ICU and death," Coljin says.

Not knowing how much COVID is circulating makes it more difficult to know how common or prevalent long-haul symptoms are and to track the long-term health effects of infection. There is an uncalculated social and economic cost when large numbers of people miss work and children stay home from school. There is a disproportionate impact to lifting restrictions, and knowing how widespread infection is can be important to be able to assess risks to those who are immuno-compromised or otherwise vulnerable. All of this, according to Coljin, is key to understanding the pandemic's effects on British Columbians.

"We need to know how much virus there is around in order to understand some of these chronic impacts. Hopefully, reinfections won't lead to that risk. Hopefully, vaccination followed by Omicron doesn't have any of those risks to any significant degree. But hope isn't a plan."