Ottawa, Jan 21 : The proportion of Covid-19 XBB.1.5 was projected to rise to nearly 7 per cent in Canada by mid-January, Canada's Chief Public Health Officer Theresa Tam said. Tam said on Friday in a speech that XBB variants are expected to increase in Canada and it is not known whether they will become the dominant lineage. XBB.1.5 had been circulating in Canada at 2.5 per cent during the week of December 25, 2022 to January 2, 2023, Xinhua news agency reported. "Nationally, the absolute number of cases is not surging at this time, nor is there evidence of increased severity with this or other new variants," she added. "Like the winter weather, it can be difficult to predict exactly what we are going to see next but we do know it's too early to put away your winter coats and boots. Similarly, it's still too early to stop taking the personal protective measures that have helped us weather the Covid storm," she said. In the statement released on Friday, Canada's National Advisory Committee on Immunisation said that booster doses of Covid-19 vaccine are an effective tool to reduce the risk of severe illness and death. /IANS