Cross Country Checkup·Ask Me Anything

Your questions about the 3rd wave of COVID-19 and vaccines answered

In some parts of Canada the third wave of COVID-19 is underway, and the number of cases caused by variants is also on the rise. Callers to Checkup had concerns about vaccinations and what they should do at this moment in time.

Two doctors answered callers' questions on Checkup's Ask Me Anything

Parts of Canada are seeing a rise in COVID-19 cases as the third wave of the pandemic arises. Of particular concern is the number of cases of variants of concern, which could hit younger people harder. (Graham Hughes/The Canadian Press)

In some parts of Canada, the third wave of COVID-19 is underway, and the number of cases caused by variants is also on the rise.

On Thursday, Ontario's Chief Medical Officer of Health Dr. David Williams confirmed the province was in a third wave, while Canada's Chief Public Health Officer Dr. Theresa Tam confirmed Sunday that there are more cases from variants of concern and it's now a "crucial moment" to try to stop that increase. 

In Regina, Sask., as many as 90 per cent of active cases are likely variants of concern, infectious disease specialist Dr. Alex Wong told CBC earlier this week. 

"Case numbers are starting to rise rapidly, you know, we're over 100 cases today reported so it's significant growth," he told Cross Country Checkup host Ian Hanomansing on Sunday. "We're seeing a lot of people get admitted into hospital now, much sicker, younger people as well. So it's happening really, really fast."

As part of Checkup's regular Ask Me Anything series, Dr. Wong and New Brunswick's Chief Medical Officer of Health Dr. Jennifer Russell answered callers' questions on COVID-19, vaccinations and the third wave of the pandemic.

Questions about AstraZeneca

Deborah McCann, calling from Kingston, Ont., explained she has relapsing-remitting multiple sclerosis and since she is immunocompromised, she is concerned about the risk of blood clots if she were to get the AstraZeneca-Oxford vaccine.

On Friday, European researchers said they found a mechanism in the vaccine that could cause very rare blood clots, and also a potential treatment for it. 

"The overall base of evidence at this point does not support a clear association between AstraZeneca vaccine administration and blood clots or bleeding in the brain, although the bleeding in the brain complication is definitely of concern," said Dr. Wong.

"If there was the ability, I think, for you to choose, I would probably lean towards one of the mRNA vaccines if you had the option," he said. "But truly, at this point, with variants spreading quickly, I wouldn't hesitate to get whatever ... you could access most quickly."

Callers to Checkup had concerns over the AstraZeneca vaccine's effectiveness. Infectious disease specialist Dr. Alex Wong encouraged them to get whatever vaccine they can get soonest. (Sam Nar/CBC)

Another caller, Bev Leroux from Toronto, was also concerned about the effectiveness of the AstraZeneca-Oxford vaccine as well as the blood-clotting issue.

Leroux said since she is 75 years old, she will be vaccinated soon but she'd prefer to get either the Moderna or Pfizer-BioNTech vaccines.

Wong said that with variants spreading quickly, if Leroux would face a delay in accessing an mRNA vaccine, but could get the AstraZeneca-Oxford vaccine right away, she should take it.

"The best vaccine and the most effective vaccine is the one that you're offered. So truly with things spreading really quickly, I would not wait," he said.

Wong said that the Moderna and Pfizer-BioNTech vaccine studies were done in the United States when there were relatively low levels of the virus circulating and "virtually no variant," while the AstraZeneca studies were done in the United Kingdom and South Africa with higher levels of the virus circulating and more variant cases. 

"When you push and you challenge a vaccine in that kind of very high transmission setting, you're going to see slightly lower numbers," he said.

He also cautioned that he expected case numbers in Ontario, where Leroux was located, could change quickly, but, Wong said, he understands that the decision over which vaccine to get is ultimately a personal one.

A pedestrian wearing a mask walks across Richmond Street in downtown London, Ont. The province is now seeing the third wave of COVID-19 cases. (Colin Butler/CBC)

Second dose question

And, on the subject of doses between vaccines, Carol Moffatt calling from Dundas, Ont. said she got her first shot of the Pfizer-BioNTech vaccine on March 2 and thought she would get the second on April 6. She then found out she wouldn't get her second shot for 16 weeks, as government guidance changed.

"Is there a deterioration of the initial vaccination that I have received? And is that a concern or not?" she asked.

"All of the information that we've received around the efficacy of the vaccine after one dose is very good," said Dr. Russell, who added that there is new research coming in about the effect of delaying the second dose.

"The data is showing that ... the efficacy stays very high, the immune response stays very high and so there isn't really a concern about it waning before that second dose," said Russell.

Hear more from Dr. Alex Wong and Dr. Jennifer Russell, as well as Cross Country Checkup's Ask Me Anything on CBC Listen


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