Should we be testing the PM?

OTTAWA • Prime Minister Justin Trudeau said he has not been examined for COVID-19 based on the advice of health care experts after his wife Sophie Grégoire Trudeau tested positive for the virus.

“It was explained to me that as long as I do not show any symptoms at all, there is no value to me being tested,” Trudeau said Friday, in a press conference where he was several metres away from reporters.

Trudeau and his family are in self-imposed isolation for two weeks after Grégoire Trudeau was found to be showing symptoms of the COVID-19 virus. She later tested positive.

The situation faced by the prime minister reflects a wider uncertainty in Canada over when people should enter self-isolation, and whether the country is testing enough potential patients as a way to get a firmer grip on the virus.

For now, the World Health Organization has said that people showing no symptoms of COVID- 19 are at “very low risk” of transmitting the virus. However, some very preliminary studies — including a recent paper that tested 135 confirmed cases in China and 93 in Singapore — suggest that infected people can potentially transfer the virus during incubation, a several- day period before major symptoms begin to emerge.

“There’s a high probability, or a substantial risk, that in fact pre- symptomatic patients, or patients with mild symptoms… could actually be contagious,” said Pierre- Gerlier Forest, director of the University of Calgary’s School of Public Policy. “You incubate it for a while.”

Forest also stressed that the studies are in their early stage, and that there is a substantial lack of information on the topic thus far.

“It’s complicated because there’s so much noise,” he said.

Trudeau said experts have advised him that he did not put staff and other contacts at risk before he entered quarantine. “According to health officials, the fact that I have expressed absolutely no symptoms means that anyone I engaged with throughout this week has not been put at risk.”

Canada had confirmed 175 cases of COVID-19 as of noon Friday, with another four presumptive cases pending.

Scientists remain highly limited in their understanding of how early the COVID-19 virus is able to spread. The study of patients in China and Singapore, which involved Canadian researchers, studied only a small sample of patients. But researchers found that the initial period, or “incubation”, is between six and 10 days, while the period of time between a patient showing symptoms and someone they infect showing symptoms is shorter, around 4.5 days.

“What that means is that people can start infecting others before they start seeing symptoms themselves,” Dr. Caroline Colijn, a professor at Simon Fraser University and co- author of the report, told the National Post earlier this week.