Canadian athletes could be affected by Beijing's higher COVID-19 testing threshold

CBC Sports has learned the Beijing Olympic Committee is using a higher testing threshold for detecting positive COVID-19 cases, making it more challenging for Canadian athletes, especially those who have recently recovered from the virus, to produce a negative test upon arriving in China.

Chief Medical Officer for the Canadian Olympic Committee Dr. Mike Wilkinson confirmed Monday afternoon the CT (Cycle Threshold) value being used in China to detect a positive test is 40.

For context, many places in Canada use 35 as the threshold value — the lower the number, the more infectious someone is. The higher the number, the less infectious the person is.

"If you're on the border of the CT value, there's no guarantee it'll be positive or negative because of persistent shedding of the virus," Dr. Wilkinson said, referring to those athletes who have recently tested positive.

The NBA and NHL use 30 as their CT value. The NFL has set its threshold at 35.

"Typically, [at] CT numbers of 30 or greater we start to think of people as less infectious. Is it perfect, no, but it's pretty good," Dr. Isaac Bogoch, an infectious diseases specialist, said.

Dr. Bogoch has concerns about how high China has set its threshold for the Games.

"It basically means that anyone with a recent infection has a not-insignificant chance of testing positive in China, even if they've had several negative tests in Canada."

There have been dozens of Canadian Olympians who have tested positive over the last number of weeks. The Canadian bobsleigh and short track speed skating teams had outbreaks. The women's hockey team have also had a high number of cases.

Figure skating duo Vanessa James and Eric Radford tested positive over Christmas. And a number of Canada's long track speed skaters have also recovered recently from the virus.

Any Games participants, should they recover from COVID-19 30 days or less from departure, have to first produce three negative PCR tests. Those documents are then submitted to the Beijing Olympic Committee. Should the participant be granted approval, two more pre-departure tests, 96 and 72-hours before the flight to Beijing, have to be produced.

"It sounds like they're treating positive PCRs as positive PCRs and not acknowledging the protective benefit that someone who is recently recovered would have. Greater transparency would be helpful," Dr. Bogoch said.

There's one final hoop for all participants to jump through upon arriving in China, and that's once again producing a negative PCR test at the airport. Should someone test positive and be asymptomatic, they are held in isolation at a hotel nearby.

Two more negative tests are then required to be released into what is being called a "closed loop" system to take part in the Olympics.