COVID-19 variants threat looms: Virus could 'take off fast', despite vaccinations across the country, Dr. Tam warns

Canada's top doctor warns of continued threats from variants of concern as more people are able to access COVID-19 vaccines across the country.

"There is indication that after coming down that second wave, that down slope, we initially sort of plateaued at about two-thirds of the way down and then we’re now beginning to see an uptick in cases," Dr. Theresa Tam, Canada’s chief public health officer said at a press conference on Friday.

"There is a risk in different areas of Canada, not everywhere, that these variants could result in the disease activity taking off fast."

While less than 10 per cent of Canadians have received a COVID-19 vaccine, Dr. Tam stressed that this is still not the time to have large gatherings. But she did say that as the weather gets warmer and more vaccines are administered, the "bubbling" concept could be something Canadians see again.

Communication around the AstraZeneca COVID-19 vaccine

Dr. Tam reiterated that the AstraZeneca COVID-19 vaccine "has not been associated with an increase in the overall risk of blood clots," contrary to some earlier concerns about this particular vaccine.

"Rare adverse events are expected to be detected when vaccines are given to millions of people," she explained. "It is possible that the vaccine may be associated with very rare but serious cases of blood clots associated with low levels of platelets, which merits further analysis."

"Health Canada will continue to work with international regulators and review data and evidence as it becomes available. The benefits of the AstraZeneca COVID-19 vaccine in protecting Canadians from COVID-19 continues to outweigh the risks."

Dr. Marc Berthiaume, the director of the Bureau of Medical Science at Health Canada, also provided more clarity on the existing data related to the AstraZeneca vaccine.

"When you look at the data around these very rare types of blood clots associated with low platelets, the information that was provided by the European Medicines Agency is that there were 25 cases over 20 million people vaccinated with the AstraZeneca vaccine," Dr. Berthiaume explained. "These adverse events are extremely rare."

"There is a subset of those adverse events, 17 of those 25, that are called [Cerebral venous sinus thrombosis] that are continuing to be investigated."

Cerebral venous thrombosis is when a blood clot occurs in the brain’s venous sinuses, causing a stroke.

Dr. Tam also stressed the importance of communicating updates throughout the pandemic and identified that a key challenge is that the information and science keeps "moving at a very fast pace."

"There will be more support to NACI [the National Advisory Committee on Immunization], for example, in communicating their recommendation, including not just the publication of their statement but a more plain language version of that," she said. "Providing more technical briefings as a sort of regular occurrence so that anytime those recommendations are put out,...helping the public understand what led to the recommendation in the end."