Canada's chief public health officer Dr. Theresa Tam said Friday that while the known cases of the Omicron COVID-19 variant have been mostly mild or asymptomatic in Canada, most of the cases are among younger people and cases have not spread into higher risk groups. However, she said officials have seen the "full spectrum of illness," including hospitalizations in the U.K., for example, and therefore "we mustn't dismiss" the variant "lightly."