One way to test vaccines is through human challenge trials in which participants are intentionally infected with a contagious organism to expedite the process of assessing the vaccine’s effectiveness. Some experts believe challenge trials may play an important role in fighting COVID-19, especially if the vaccines under current study do not demonstrate sufficient efficacy, if spread of COVID-19 is controlled to a point that radically slows down traditional trials, or if new vaccines need to be rapidly developed for specific subpopulations.1 (...) Challenge trials involve significant time, burden and risk, requiring participants to spend 3–6 weeks in legal quarantine for 24 hours a day in a high-security facility. During this time, no inperson visitors will be allowed, except for very limited inperson contact from researchers collecting necessary data and checks. Following the quarantine period, participants will be asked to attend numerous outpatient follow-up visits over the course of months, to further monitor their response to the vaccine. Participation involves being away from family who may themselves become sick during the global pandemic, as well as potential fear and mental anguish around being a ‘first’ subject. Because there is no definitive treatment for COVID-19, participants could experience serious illness. But even with milder illness, medical experts know very little about the long-term consequences of COVID-19 infection. This raises the question of how much people should be paid for their participation in COVID-19 challenge trials. Most think participants should be paid something, but many contend that we should be …. (shrink)