BC’s Covid-19 tests caught just 1 out of 8 cases, UBC antibody study shows

    BC’s testing rate for Covid-19 caught only 1 out of 8 infections.

    While the government was reporting 2,000 cases towards the end of May, a UBC antibody study shows the province had an estimated 16,500 actual cases.

    If that projection stands BC’s current official count of 3,149 tested cases would translate into 25,192 actual cases.

    The study from blood samples drawn by Lifelabs showing the high number of undocumented cases raises concerns about the actual spread of the virus.

    It cited a previous study in Wuhan, China, that demonstrated undocumented cases were major drivers of known infections.

    Lead author Danuta Skowronski is Epidemiology Lead of Influenza & Emerging Respiratory Pathogens at BCCDC, Clinical Professor at UBC.

    “A majority of COVID-19 infections (in Wuhan) were undocumented prior to implementation of control measures on January 23, and these undocumented infections substantially contributed to virus transmission. (Ruiyun Li et al. medRxiv. 2020.)

    “Applying this 0.55% age-standardized sero-prevalence point estimate to the Lower Mainland source population (~3 million), we estimate about 16,500 infections, or about 8 times higher than the ~2000 cases reported,” the UBC serology study concluded.

    “Until early April, however, BC targeted SARS-CoV-2 testing to people with exposure and/or high-risk indication, leading to a per capita testing rate that was also below other provinces,” the study says.

    This fact also led to a complaint by BC hospital doctors that they were sending people home without testing when they had demonstrable symptoms of Covid-19.

    “Like elsewhere, all-cause deaths in BC exceeded tallies of the previous 5 years (during a six- week period spanning March 15 to April 25).

    “Taken together these statistics have led to speculation that BC may have experienced more undocumented SARS-CoV-2 infections that, in conjunction with asymptomatic cases, contributed to unrecognized community transmission,” the UBC study adds.

    With less than 1% infection rate found in the antibody tests there’s both success in suppression and concern about susceptibility for more infections, the study noted.

    The study praises BC for measures taken to suppress transmission.

    “When on December 31, 2019 a cluster of SARS-like illness became known in Wuhan City, China, the BC Centre for Disease Control (BCCDC) responded rapidly, disseminating provincial alerts that morning and repeatedly over the ensuing weeks.

    “Ultimately, the Wuhan cluster became the coronavirus infectious disease 2019 (COVID-19) pandemic attributed to novel SARS-CoV-2.

    “Although no airport in Canada receives direct flights from Wuhan, the earliest COVID-19 onset date in Canada (January 15) was a case arriving indirectly from Wuhan to Vancouver, with the earliest reported cases otherwise in Canada also among travelers arriving indirectly from Wuhan to Toronto, Ontario (January 25) or Vancouver, BC (January 27).

    “Thereafter, BC also reported the first importation of COVID-19 from outside China (Iran) on February 20; the first super-spreading event on March 6; and the first long-term care facility outbreak (and associated death) on March 9.”

    This reference to LTC is the Lynn Valley outbreak which caused 79 infections and 20 senior deaths.

    “Despite these firsts, BC has been recognized for its successful control of COVID-19 during the winter-spring 2020.

    “Early success was attributed in part to timely alerting; sustained media messaging through a single health official; rapid development and deployment of diagnostic testing; and restriction of staff movement between long-term care facilities.

    “As elsewhere in Canada, on March 12 the province recommended against non-essential travel that preceded the March 16 start of the usual two-week spring-break for schools; whereas, in other provinces (e.g. Quebec), spring break began two weeks earlier (March 2) and families were already returning from trips abroad.

    “In BC, a period of population-level mitigation measures, incorporating further travel restrictions, bans on public gatherings and closure of personal service establishments ultimately spanned ~2 months, with re-opening beginning gradually by May 19.

    “This period captured the beginning and end of peak COVID-19 case reporting, corresponding with first wave activity in BC.”

    “Although other areas enacted similar control measures, BC has consistently reported amongst the lowest COVID-19 case and death rates compared to other provinces in Canada, adjacent west coast states in the United States, or elsewhere globally.”

    The above conclusion appears curious and disregards the fact that BC’s deaths are third highest in Canada after larger population provinces such as Quebec and Ontario.

    All other provinces and jurisdiction have lower death rates.

    BC has 189 deaths whereas Alberta stands at 163.

    Alberta also has tested more than 500,000 people while BC’s testing is just over 200,000 (producing the low numbers the study discusses)

    Washington State has a far higher case load and case fatalities but the state is open to road, rail, marine and air travel to and from high infection American jurisdictions.

    The UBC study was a snapshot of two periods – March and May, close to the entry into phase 2 of opening.