Some Volunteers Want To Be Infected With Coronavirus To Help Find A Vaccine. But It Isn’t That Simple.

Some Volunteers Want To Be Infected With Coronavirus To Help Find A Vaccine. But It Isn’t That Simple. Gavriel Kleinwaks wants to get COVID-19, and she can’t understand why I find that surprising. The 23-year-old grad student is one of more than 30,000 volunteers… chadwickmatlin FiveThirtyEight

Gavriel Kleinwaks wants to get COVID-19, and she can’t understand why I find that surprising. The 23-year-old grad student is one of more than 30,000 volunteers who have signed up with an organization to be potential participants in a human challenge trial for COVID-19 vaccines. If selected, she would be given a dose of the vaccine and then given a dose of the live virus to see how well the vaccine works....

Given the urgency to find a vaccine for COVID-19, these kinds of trials are attracting a lot of attention from researchers, bioethicists and the public at large. It’s encouraging that there are tens of thousands of people like Kleinwaks willing to put their health, and their lives, on the line to get a vaccine sooner.

But human challenge trials are not as simple a proposition as they seem, and there’s ongoing debate within the scientific community about whether the risks outweigh the benefits.

In the normal course of vaccine development, the vaccine is tested for efficacy in what’s called a phase 3 trial. A large number of people are given either the vaccine or a placebo and then sent back to live their lives, assuming that some of them, at some point, will be exposed to the virus. If a large percentage of the people who got the vaccine never become infected, and people who got the placebo do, you know the vaccine works. In a human challenge trial, rather than waiting for participants to encounter the virus naturally, the researchers go ahead and expose participants to the virus directly (this can be done in a variety of ways, from ingesting it orally, to dripping a virus-laced fluid into their noses). Participants in the trial stay in a secure medical facility and are treated if they get sick.

In theory, it’s a really practical design. Want to see how someone with the vaccine does when exposed to the virus? Just expose them to the virus! But even in the best-case scenario, these kinds of trials require a lot of ethical considerations. And the novel coronavirus, a pathogen we’re still only just beginning to understand, is not the best-case scenario.

Human challenge trials have been used in the past to study everything from seasonal flu to malaria, but there are noticeable differences between those diseases and COVID-19. In the case of flu, the risk of serious illness or death for healthy participants is low. In the case of malaria, we have proven treatments that cure the disease. We don’t have the same luxuries with COVID-19, which means it doesn’t meet some of the regulations that medical ethicists have laid out for researchers considering using a human challenge model.

“We traced a pretty clear line in the sand saying that you couldn’t do challenge studies if participants would be exposed to risk of irreversible, incurable or possibly fatal infections,” said Charles Weijer, a bioethicist at Western University in Canada who co-authored expert criteria for human challenge trials. As a result, he said, COVID-19 trials, are “not currently ethical.”

Researchers who have proposed considering human challenge trials for COVID-19 vaccines say those risks can be mitigated by enrolling healthy, young participants at a lower risk of serious or deadly infection and providing access to high-quality medical treatment....