Since the early days of the pandemic, some researchers have advocated a fast way to determine whether a COVID-19 vaccine works: Intentionally attempt to infect vaccinated volunteers with the virus, SARS-CoV-2.
Ethicists and vaccine scientists alike raised red flags, and the discussion has remained mostly theoretical. But now two key elements are taking shape: a large corps of volunteers willing to take part in a “human challenge” trial, and the well-understood lab-grown virus strains needed for the studies.
The volunteers come from an advocacy group, 1Day Sooner, that has signed up more than 30,000 people from 140 countries. The group, co-founded by a 22-year-old, organized an open letter that was signed by 15 Nobel laureates and 100 other prominent researchers, ethicists, and philosophers, which it sent to U.S. National Institutes of Health Director Francis Collins on 15 July.
The letter urged the U.S. government “to undertake immediate preparations for human challenge trials” in young, healthy people, who are less likely to suffer severe disease from COVID-19. Among the signatories was Adrian Hill of the University of Oxford, whose lab developed one of the leading COVID-19 vaccine candidates and plans to produce virus strains that could be used in the trials.
Researchers use human challenges to test vaccines for other diseases, including cholera and malaria, but in those experiments, proven drugs can help “rescue” study participants if the vaccine doesn’t work and they become seriously ill. In a June report on COVID-19 vaccine challenges, an advisory group to the World Health Organization (WHO) was split over whether they should take place in the absence of a rescue treatment.
The group was also evenly divided on whether human challenges would truly speed the vaccine effort, given that efficacy trials using participants at risk of natural infection have already begun. Still, the report offered guidelines for these trials, suggesting they should recruit volunteers between ages 18 and 25 and require them to remain in “high-level isolation units” during the study so they don’t infect others.
Sophie Rose, 22, says she is ready to take part. She co-founded 1DaySooner with Josh Morrison, a Harvard Law School graduate who, in 2014, helped start Waitlist Zero, an advocacy group for kidney donations. Rose earned her bachelor’s degree in biology from Stanford University in 2019 and that December moved to the University of Oxford to work on cancer research, hoping to tour Europe during breaks. Because of COVID-19, she has not yet had the chance to leave Oxford. “It’s been a weird, weird turn of events,” says Rose, who plans to study epidemiology at Johns Hopkins University’s Bloomberg School of Public Health in the fall.