TORONTO — Researchers expect it will take at least a year to develop a safe and effective vaccine for COVID-19, a lengthy process that involves injecting healthy people with potential vaccines and then waiting weeks or months to see if those individuals fall ill.
But thousands of healthy volunteers, including hundreds of Canadians, have offered to try a far riskier approach: getting injected with a potential vaccine and then purposely becoming infected with COVID-19 to test if the vaccine works.
The method is called a “human challenge trial,” and it’s been used before to develop treatments against smallpox, influenza and malaria. The World Health Organization says the approach can be “substantially faster” than standard vaccine field trials and, if designed properly, human challenge trials could lead to better vaccines.
But purposefully infecting healthy individuals with a potentially deadly virus has obvious ethical concerns, including the inherent risk of life-altering side-effects or death.
So far, no country has launched a human challenge trial for COVID-19. And even if one was launched, some scientists are skeptical that testing young, healthy people is the right way to develop a vaccine for an illness that predominantly kills the elderly.
But volunteers behind 1 Day Sooner, an international campaign to gather participants for a potential human challenge trial, say the risk is worth it. They’ve already recruited 16,000 volunteers from 102 countries, including Canada.
At least 300 Canadians have signed up for the effort, including Conor Barnes, a 27-year-old from Kelowna, B.C. Before volunteering, he weighed the risks to his own health against the possibility of helping save thousands of lives.
“It’s the time for outside-the-box thinking and approaches, because the costs right now to the entire world are so high,” Barnes told CTV News.
“There is a chance of dying, so that’s a concern.”
The campaign was created six weeks ago in New York City, the epicentre of the American outbreak, by attorney Josh Morrison. He was feeling depressed and helpless at home when he stumbled upon an article about human challenge trials.
“I thought, ‘Well, that sounds like a good idea.’ I definitely want this to be over with as soon as possible,” Morrison told CTV News.
Participants with 1 Day Sooner haven’t officially registered for a human challenge trial. By signing up, they are simply expressing interest in a potential future trial and providing their contact information.
Regardless, Morrison called the wave of support “unbelievable.”
“Just to see other people make this sacrifice and take on this risk in trying to help, it’s just incredibly moving. And it’s a very bright light in a very dark moment.”
TESTING IN CANADA
Health Canada has not received any applications for human challenge studies for COVID-19 vaccines. But a spokesperson for the federal agency said it “could be possible” to conduct such a study “if carefully controlled.”
“However, before doing so, we need to have sufficient information about the potential risks of the virus and how to mitigate them,” spokesperson Andre Gagnon told CTV News in an emailed statement.
“If an application is submitted to Health Canada on a human challenge trial, part of the considerations that would go into the assessment would also include international best practices.”
WHO OFFERS GUIDANCE
In response to growing interest about human challenge trials, the WHO issued a set of guidelines in the event that one is launched.
Participants should be between the ages of 18 to 30 with no underlying health problems. That demographic group has an estimated hospitalization rate of around one per cent and a fatal infection rate of 0.03 per cent, according to WHO numbers.
The WHO also advised that participants should be given a “low” dose of the virus — enough to cause illness, but not severe disease. Any such study should be conducted in a secure facility to avoid infecting others and should meet especially high standards.
But Jonathan Kimmelman, a professor of biomedical ethics at McGill University, expressed concerns about the risks. Researchers are still learning about how COVID-19 affects different types of people, and there are currently no “rescue medications” that could be given to a healthy volunteer who develops severe complications.
Given those factors, Kimmelman said it’s unclear whether the approach is appropriate so early in the pandemic.
“Many people are saying they might speed up the process of developing a vaccine. Because we’re so new into the process of developing a vaccine for COVID-19, it’s not yet 100 per cent clear how much we actually really need this technique to advance the pace of vaccine development. It might turn out to be crucial. It might not,” he said.
He added that human challenge trials shouldn’t be considered a substitute for more standard field studies, which take longer but typically study a wider demographic pool.
“The kinds of people that we actually need to use the vaccine are often going to be people who are not like healthy 20-year-olds. They’re going to be in elderly populations, people who are immunocompromised and whatnot,” he said.
Another concern is that most of the vaccines are being produced by corporations. Kimmelman said tough rules are needed on how the studies are conducted and transparency on the results.
“So, for example, you want to really make sure that regulators in Canada or United States are really vetting the data from those trials carefully to establish that the vaccine is safe enough and effective enough to deploy in a large population.”
THE SAFETY QUESTION
In an interview with the journal Nature, Nir Eyal, the director of the Center for Population-Level Bioethics at Rutgers University, said the risk to participants could be reduced by closely monitoring their health and providing them with “excellent treatment immediately” should they become infected.
“It might even be curiously safer for some to join the study than to await probable infection and then try to rely on the general health-care system,” Eyal said.
Human challenge trials sometimes raise difficult ethical dilemmas. In 2017, a human challenge trial for Zika virus was shot down by ethicists in the United States because it posed too much of a risk to participants’ sexual partners and their own long-term health.
But Eyal said there is a major difference between Zika and COVID-19 — namely, that testing a COVID-19 vaccine on healthy volunteers wouldn’t endanger their sexual partners.
He also expressed a belief that, sooner or later, more countries will begin looking at human challenge trials as key to combatting the pandemic.
“Do I believe that countries will jump on board? Judging from the response we are getting from various stakeholders since publishing the preprint, I believe that many will.”
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