Omicron | Infected people can be contagious for up to ten days, says Dr Tam

(Ottawa) The D^D Theresa Tam says the latest data does not support the conclusion that the Omicron variant is contagious for less time than previous strains of the virus that causes COVID-19.

The Chief Public Health Officer appeared before the House of Commons Health Committee on Tuesday. Answering questions about the reduction by several provinces, including Quebec, of the isolation period from ten to five days for infected people, she conceded that the lack of manpower caused by the very large number of infections could justify adjusting our risk tolerance by reducing the isolation period.

“It’s a tough decision for the provinces to make,” she acknowledged.

Three weeks ago, the US Centers for Disease Control and Prevention (CDC) claimed that Omicron appeared to be most contagious around two days before symptoms appeared and three days after, which logically reduced the period of isolation to five days on the condition of wearing the mask thereafter.

In Canada, the rules on isolation are set by the provinces and territories, with the exception of those affecting international travellers.

While the Public Health Agency of Canada continues to recommend isolation for ten days after a positive screening result or the onset of symptoms, all provinces and territories have stopped adhering to this guidance.

Nova Scotia, Prince Edward Island and Newfoundland and Labrador, as well as the territories of Yukon and Nunavut, have reduced the isolation period for those vaccinated from ten to seven days. All other provinces and the Northwest Territories allow vaccinated people to self-isolate for only five days.

Across Canada, unvaccinated people must still isolate themselves for ten days in the event of infection.

The D^D Tam was asked by Commons MPs on Tuesday when Canada would adjust its isolation guidelines. The Chief Administrator replied that her team is working on it, but information is missing.

She argued that data on Omicron variant infections is still limited around the world and that data collection in Canada continues.

She pointed to a study from Japan, which has not yet been peer-reviewed, but which indicated that the viral load was highest in Omicron patients three to six days after the onset of symptoms and disappeared after about 10 days.

Omicron would therefore be no different from previous strains of SARS-CoV-2.

Nevertheless, the D^D Tam reiterates that this doesn’t necessarily mean you can’t adjust isolation periods if you make sure you add the right precautions. Mask-wearing and effective screening thus become even more important.