Omicron COVID-19 variant is infectious for up to 10 days, Tam says

The Public Health Agency of Canada recommends people infected with COVID-19 isolate for at least 10 days after they test positive or symptoms begin, whichever came first.

The latest evidence does not show the Omicron variant is contagious for less time than previous versions of the virus that causes COVID-19, chief public health officer Dr. Theresa Tam said Tuesday.

But Tam told the House of Commons health committee that the sheer number infections from Omicron is stressing workforces and is a reason to adjust our risk tolerance for ending isolation periods early.

“This is a difficult decision that the provinces have to make,” Tam said.

Three weeks ago, the United States Centers for Disease Control said data on infectious periods supported cutting the isolation period to five days from 10, if people wear masks after leaving isolation.

That was based on data the CDC said suggested Omicron was most infectious for about two days before symptoms started and for three days after.

In Canada, quarantine rules are set by provinces and territories, except as it relates to international travellers. But the Public Health Agency of Canada still recommends people infected with COVID-19 isolate for at least 10 days after they test positive or symptoms begin, whichever came first.

Every province and territory has stopped following that advice, starting with Ontario and Saskatchewan on Dec. 30.

Nova Scotia, Prince Edward Island and Newfoundland and Labrador, as well as Yukon and Nunavut, cut the isolation period from 10 days to seven for vaccinated people. Every other province and the Northwest Territories say five days.