Study suggests 8 times more people in B.C. infected with virus than confirmed

VANCOUVER -- A new study suggests eight times as many people in Metro Vancouver have been infected by the novel coronavirus than the rate of reported cases.

The joint study by researchers at the B.C. Centre for Disease Control, University of B.C., LifeLabs and public health scientists is posted on the health research website medRxiv and a news conference on the findings is scheduled for Thursday morning.

The authors say the findings indicate successful suppression of community transmission in B.C., with an estimated overall infection rate of less than one per cent.

The study looked at anonymous blood samples collected for reasons unrelated to COVID-19 by LifeLabs in March and May, before and after public health measures were introduced.

The first samples in March found two of 869 specimens were positive, for a prevalence of 0.28 per cent, while the May sample found a prevalence of 0.55 per cent.

Health Minister Adrian Dix described the estimated infection rate as “very low” and says it shows the effectiveness of British Columbia's public health measures and co-operation of the public.

“It reinforces the fact that we're on the right track,” Dix says.

“Of course, this is as the study suggests a dual-edged question, a low level of transmission but also very few people with antibodies to deal with potential future spikes of COVID-19.”

If the study's prevalence rate is applied to the whole provincial population, it could mean about 28,000 people have had the novel coronavirus, while 3,149 cases of COVID-19 have been confirmed to date, however Dix noted the results are specific to the Vancouver area.

Health officials have repeatedly said that more people have been infected with the virus than have tested positive and Dix calls the estimated prevalence rate in B.C. “encouraging.”

“Overall the level of infection in B.C. was low and that's due to the actions of people in B.C. That said, there are more people who were infected with COVID-19 than tested positive and that's something we've said clearly, especially in the period of March and April when we were focusing our testing program particularly on specific groups including health-care workers,” Dix says.

The study is the first of its kind in Canada, he says.

The study is also important because it involved people who did not self-select for COVID-19 testing, so they likely didn't believe they had the virus, Dix says.

The study was authorized by provincial health officer Dr. Bonnie Henry and approved by the clinical research ethics board of the university. It has not yet been peer reviewed.

British Columbia recorded 21 new cases Wednesday and no new deaths. There are 207 active cases while 2,753 people who tested positive have recovered, the government said in a news release.