University prof opposes human challenge trials for COVID-19

The federal government has until early December to say whether it will approve the use of human challenge trials to test COVID-19 vaccines.

In human challenge trials, healthy volunteers are deliberately infected with COVID-19 in order to test a vaccine.

The UK has announced that it will begin challenge trials for COVID-19 vaccines in January 2021. Liberal MP Marcus Powlowski presented an e-petition to the House in late October calling for the federal government to follow suit.

However, a university research professor at Dalhousie University says she doesn't want to see Canada go this route.

Typically when a vaccine is being tested, people are split into two groups. Some are given the actual vaccine and some get a placebo as a scientific control measure. They are then tracked to see who eventually comes down with the disease the virus causes, explained Françoise Baylis, speaking with Island Morning's Laura Chapin.

"A challenge trial follows a similar procedure, except they don't want to take time for people to go out into the world and perhaps encounter the virus. They want to actually inject people purposely with the virus," she said.

That means some would get the vaccine in development, some would receive the placebo, containing no active medical substances — but afterwards, everyone in the trial would be infected with the coronavirus that causes COVID-19.

"The concern we have there is with this idea you would purposely infect someone knowing that they don't even have the potential of mounting some kind of immunity because they only received a placebo," she said.

"That's what we want to avoid. We want to avoid putting humans in that position."

Challenge trials likely not needed

As well as speaking with Baylis, CBC P.E.I. contacted the MP who introduced the petition calling for human challenge trials in Canada. Powlowski now says that because two vaccine companies appear to have promising early results, he doesn't feel such trials are needed here.

Human challenge trials have been used in the past, Baylis said — with one important difference.

"One of the things that is really important to appreciate is that when those kinds of challenge trials have happened, the researchers have something to offer in the event that somebody unfortunately becomes sick," she said.

We have 12 potential vaccines in Phase 3. And three of those 12 have already issued promising results.- Francoise Baylis

But at the moment, there is no guaranteed emergency treatment to stave off the worst effects of COVID-19.

At this point there isn't a need for any challenge trials in Canada, because vaccines which are in development have showed promising results using the traditional method of one vaccinated group and one unvaccinated group it would then track to see if and how they reacted when infected with COVID-19, Baylis said.

Some vaccines are hitting their final phase before approval, Baylis said.

"We have 12 potential vaccines in Phase 3. And three of those 12 have already issued promising results," she said. "I think that using the traditional approach, we have made fast, fast progress."

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