Infectious disease experts say B.C.'s decision to not count COVID-19 reinfections in weekly case updates may be painting an incomplete picture of the impact of the disease on British Columbians.
According to an emailed statement from a B.C. Centre for Disease Control (BCCDC) spokesperson, B.C. hasn't captured cases caused by reinfections since daily case reporting switched to a weekly format in April.
"Cases are linked to the first positive COVID-19 PCR test result," the spokesperson said.
"[The number of] people with COVID-19 infection currently in hospital or critical care … is based on the most recent test performed."
Experts have already noted that B.C.'s testing capacity is significantly restricted, especially the more accurate PCR tests, which are reserved for vulnerable populations.
Dr. Caroline Colijn, a mathematician and Canada 150 research chair at Simon Fraser University, said that without counting reinfections, residents could get an inaccurate picture of how the pandemic was playing out in the province.
"[This] probably didn't matter at first, when there were very few reinfections because very few people in B.C. had COVID," she told CBC News in an interview.
"As time goes on, it's going to change. Because the more people that have COVID, the more people are at risk of reinfection for COVID."
Colijn, who is a member of B.C.'s independent COVID-19 modelling group, said not counting reinfections could lead to a "substantial" underreporting of COVID risks in B.C.
The BCCDC spokesperson did not say why reinfections were not counted in weekly statistics but said they would be "working to update the data system" to better quantify them.
Dr. Tara Moriarty, an infectious diseases researcher at the University of Toronto and the founder of COVID-19 Resources Canada, said there was no valid reason for B.C. not to count reinfections.
"It's not helpful for understanding the COVID situation. In fact, it obscures the COVID situation even more," she said.
Moriarty added that other provinces, like Quebec and Manitoba, were much more accurate with their COVID reporting compared to B.C., and that she wasn't aware of other provinces excluding reinfections from their counts.
Most provinces do not say whether case counts are linked to first positive PCR tests, although Saskatchewan has noted that as of September, it has started counting people who have tested positive more than once in 90 days, or further, apart.
Could further impact vulnerable groups
Colijn said not counting reinfections was particularly alarming given a study co-authored by Provincial Health Officer Dr. Bonnie Henry showed more than 60 per cent of Lower Mainland residents were infected during the first Omicron wave.
She said that B.C. would continue to miss more and more cases under the counting method as time went on — especially among vulnerable groups who are likely to have a positive PCR test on file already.
"The fact that it changes over time, that people at risk might be at risk again — we're potentially missing a higher and higher portion of the severe outcomes as we move forward," she said.
Colijn said that the province was not accurately communicating the long-term risks of COVID that aren't hospitalizations or deaths, such as the risk of cardiovascular damage and long COVID and that not accurately reflecting cases could mean those severe outcomes aren't visible immediately.
An email sent last month to a member of the modelling group from a senior BCCDC official and seen by CBC News states that reported deaths and hospital admission numbers are also linked to the first positive PCR lab test.
In the email, the official says they do not believe that reinfections constitute a significant proportion of reported cases — less than one per cent, though they note there may be more reinfections in the wider population.
Moriarty said that assessment was inconsistent with data across Canada and the world and estimated that reinfections were "substantial" across B.C.
"If you look at data from the U.S. Veterans' Administration, reinfections are really quite common, including among people who are hospitalized," she said.
Moriarty said underreporting COVID data could give residents false hopes about the state of the pandemic.
"I'm really concerned that we're just kind of blindly walking into something worse," she said.