Opinion: Placebo arms aren’t needed for challenge trials of Covid-19 vaccines
To control the Covid-19 pandemic, we need an effective vaccine against SARS-CoV-2, the virus that causes this highly infectious disease.
Some argue that we should speed up the development and testing of new vaccines by using human challenge trials, in which volunteers who have received a candidate vaccine are deliberately exposed to the coronavirus. We agree with this view, but question the proposed methodology of these trials.
