The push toward a coronavirus vaccine continues, with several candidates now in various stages of clinical trials. So far, the biggest ethical question surrounding a vaccine is whether to mandate it for everyone. But there is another ethical dilemma that could determine if, or how fast, we even get a vaccine. Some companies developing vaccines are considering using so-called human challenge trials. "A human challenge trial basically means deliberately giving someone the COVID-19 virus in a weakened form, to see whether experimental vaccines might help prevent you getting infected," says Dr. Arthur Caplan, bioethicist at NYU Langone Medical Center.
Human challenge trials have been used in the past on vaccines for typhoid, cholera and malaria, among other diseases. But with no cure and only a few known treatments for COVID-19, deliberately infecting healthy people with the virus raises unique concerns. "You want to pick people for the challenge study who are volunteers---we're not going to drag anybody in and say you must do this---and you also want to take younger people, because they don't seem to be as adversely affected by the virus," says Dr. Caplan.
Dr. Caplan supports human challenge trials for a COVID-19 vaccine, if done in a limited group and a controlled setting. In fact, he believes one of the advantages of this method is it requires far fewer than the tens of thousands of volunteers used in a normal clinical trial. "If you do a challenge trial, you might only need 500 people," he tells KTRH. "You know exactly where they are, you keep them in a hospital facility, and you watch."
So far, opinion on human challenge trials seems to be split among those working on a vaccine. Some agree with Dr. Caplan, while others say it raises too many risks and isn't necessary to develop a working vaccine. Still, he believes it will happen. "I know that preparations are underway to start making those weakened versions of the virus, to get ready to do this," says Dr. Caplan. "I think we're going to see it, that would be my prediction."