More dangerous variants of COVID-19 recorded recently are just the tip of the iceberg: Dr. Theresa Tam

Canada's top doctor says now is not the time for Canadians to increase their contact with others in light of a recent rise in average COVID-19 case counts across the country.

Dr. Theresa Tam says this upswing combined with an acceleration of new variants of the virus in Canada is cause for concern.

She says the most up-to-date stats indicate the percentage of Canadians with immunity to COVID-19 remains low, even as governments have been ramping up their vaccination efforts.

And since today's case numbers reflect the situation in Canada two weeks ago, Tam urged Canadians to continue to keep their bubbles small, or the vaccines won't have time to take effect.

Dr. Tam also reassured Canadians that Health Canada remains confident the Oxford-AstraZeneca COVID-19 vaccine is safe, despite concerns raised in Europe about alleged adverse side-effects, such as blood clots, that may have affected a small number of people who have received the vaccine.

Deputy chief health officer Dr. Howard Njoo says the benefits of all vaccines approved for use in Canada greatly outweigh any potential risks.