“The conventional next step would be phase three trials, in which thousands of participants at risk of the targeted infection are randomized to receive either the vaccine or a control placebo. The trial participants are then monitored by researchers as they go about their usual lives to see how many of the vaccinated people (vs. those in the placebo group) actually come down with the disease. This stately process of evaluation takes a considerable amount of time to unfold.
Human challenge trials, also known as controlled human infection studies, would greatly speed up the process of identifying effective vaccines and treatments for the virus responsible for the COVID-19 pandemic. Consequently, some prominent bioethicists are arguing that it’s time to recruit some healthy and willing young people, inject them with various experimental coronavirus vaccines, and then expose them to the virus to see if any of the vaccines work. Instead of waiting around for the virus to find (vaccinated and unvaccinated) folks in the wild—as researchers do in regular phase three trials—human challenge trials speed things up by purposely bringing the virus to the study participants.”
“As of press time, pharmaceutical companies such as Moderna and Pfizer seemed content to dawdle along with conventional phase three trials, but we can hope that that will change. Human challenge trials could really crank up the warp factor in the search for an effective COVID-19 vaccine.”