The prospect of a widely available severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine is an increasingly high priority for an effective response to the coronavirus disease 2019 (COVID-19) pandemic and an area of intense interest and attention for professionals, politicians, and the public alike. The understandable desire for such a vaccine has led to significant discussion and even some planning for the possibility of human challenge studies (HCS) as a tool for accelerating the process for identifying, testing, and developing an effective vaccine
Typically, undertaking HCS in vaccine development requires that the disease for which a challenge would be introduced either has an available rescue therapy to treat those who become infected or the disease is known to be self-limiting. There is no rescue therapy for SARS-CoV-2 infection, and proponents of HCS have claimed that the infection is likely to be self-limiting and mild in young, healthy volunteers based on current understanding of the infection. If accurate, the basic requirements for undertaking an HCS could be met if conducted with that population. Proponents further argue that such HCS are ethically acceptable in the current pandemic. Most critically, they contend that these studies are likely to speed the development of effective vaccines.
But based on our assessment of these arguments, we disagree. We believe it is unethical to move forward with such trials at the current time. Whereas proponents of these studies suggest that such studies will accelerate the time to approved vaccines, the facts fail to support these claims. HCS to address SARS-CoV-2 face unacceptable ethics challenges, and, further, undertaking them would do a disservice to the public by undermining already strained confidence in the vaccine development process.
