OTTAWA -- As several provinces suspend the first dose of AstraZeneca, and questions remain about whether a second shot will be green-lighted, the researcher who oversaw the development of the vaccine says the move is not only flawed but may lead to serious consequences.

Oxford University regius professor of medicine Sir John Bell told CTV News’ Question Period, Canada’s approach to AstraZeneca use specifically is reflective of the country’s overall vaccine strategy: “acting on a lot of hearsay not facts.”

“At my last look you guys are 3.6 per cent vaccinated with two doses, so just wait for the [B.1.617 variant] to rip through the Canadian population, and then the problems you've had with these very rare clotting events will look pretty insignificant,” said Bell.

“Unless you've got two doses of mRNA vaccine sitting in a back room, you need to get on and vaccinate people… all this messing around, is going to cost lives. This is a public health decision, it's not, you know it's not some academic game.”

Nova Scotia and Manitoba both announced new restrictions on the use of the AstraZeneca vaccine last Wednesday, following similar news out of Alberta, Saskatchewan, Ontario and Quebec a day earlier. The reasoning for the halt is twofold: rising caution over rare blood clotting incidents and a shortage of supply.

For most, the plan is to stop offering first shots of AstraZeneca and to hold on to any outstanding vials to distribute as second shots to those who already have the first. Though in Ontario, provincial Health Minister Christine Elliott said a decision has yet to be made about whether AstraZeneca will still be offered as a second shot, leaving open the potential to let doses expire before that call is made.

The National Advisory Committee on Immunization (NACI), which provides advice on the use of vaccines in Canada, has been criticised for causing vaccine confusion and hesitancy around AstraZeneca, after saying mRNA vaccines were “preferred.”

In a separate interview on CTV’s Question Period airing Sunday, Health Canada’s chief medical adviser Dr. Supriya Sharma responded to Bell’s comments stating that while AstraZeneca’s benefits outweigh its risks, Canada should take advantage of an influx of mRNA supply arriving in Canada.

“We were always going to have this pivot point about how we were going to use the vaccines that are coming in…so what provinces are looking at right now, they’re looking at the supply they have, the number of first doses that have been given, the plans they need to reserve second doses and then overall what’s happening with COVID-19 in their provinces,” she said.

Bell directly opposed this notion, stating “there is no time to wait” on the second dose.

“What we can see is that the more people with a second dose, the more people will have antibody levels that are high enough to deal with the [B.1.617 variant], which is where we are at the moment, in the U.K. So my advice is get people two doses, as fast as you can and hunker down,” he said.

“For the Canadians to be out thinking about whether they should have a second dose, you know, eating marshmallows around the campfire looks a bit silly to me frankly.”

And on the mixing of vaccines, Bell, who has intimate knowledge of the study currently taking place at the University of Oxford, said initial findings show severe side effect outcomes.

“Our experience to date is that it produces pretty severe reactogenicity, so severe that we don't think that's going to be viable and by that I mean, you get your second dose if you flip it over, you'll get really sick, so I would not advise that,” he said.

“And the second dose of AstraZeneca, which we now put in many, many millions of people who had a first dose of AstraZeneca, we’re not sure we can even find a single case of clotting problems. So, you know…this needs to be data driven.”

In response to this, Dr. Supriya Sharma said Canada will wait to consider the entire results of the study before making recommendations.

Prime Minister Justin Trudeau has said his doctor recommended he receive a second dose of the AstraZeneca, and Conservative Leader Erin O’Toole said he would welcome one on CTV’s Question Period.

“Yeah, I will take my shot. I've looked at the approval and it's safe, it's effective as indicated,” he said, adding that the federal government is the source of vaccine confusion and should be responsible for streamlining public health messaging.

“The confusion that comes is from the changing message. The prime minister said, take the first vaccine that comes available. A few days after that NACI said conflicting advice. People are worried, this is a third wave that they don't see happening in the United States and they see stadiums filling up and Canada's going into further lockdowns, longer lockdowns, all because we don't have sufficient vaccine supply.”

Next week, Canada is set to receive its largest vaccine shipment to date, with 3.4 million coming from Pfizer and 1.1 million arriving from Moderna.

In the second quarter, which ends in June, Canada is expecting to receive a total of 24.2 million doses from Pfizer, between 10.3 and 12.3 million doses of Moderna, and the government had aimed to see up to 4.4 million doses of AstraZeneca arrive.

With a file from The Canadian Press & CTV News’ Rachel Aiello.