COVID-19 human challenge trials and randomized controlled trials: lessons for the next pandemic

The COVID-19 pandemic touched off an unprecedented search for vaccines and treatments. Without question, the development of vaccines to prevent COVID-19 was an enormous scientific accomplishment. Further, the RECOVERY and Solidarity trials identified effective treatments for COVID-19. But all was not success. The urgent need for COVID-19 prevention and treatment fueled an embrace of risks—to research participants and to the reliability of the science itself—as allegedly necessary costs to speed scientific progress. Scientists and (even) ethicists supported overturning longstanding norms protecting healthy volunteers in human challenge trials to speed vaccine development, but these trials led to no vaccines. Physicians, with the approval of research ethics committees, designed hundreds of unblinded, single-center clinical trials at high risk of bias to speed the identification of new treatments. But these clinical trials led to no treatments. The lesson for future pandemics is that the acceptance of greater risks to participants or science does not reliably lead to progress. We are better served by science that upholds the highest ethical and methodological standards.