“Should scientists infect healthy people with the coronavirus to test vaccines?” asks the noted scientific journal Nature. “Radical proposal to conduct ‘human challenge’ studies could dramatically speed up vaccine research,” the article subhed reads.
Scientists are racing to come up with a vaccine to protect people from the spread of a virus that is shutting down the world economy and overloading hospitals with patients in several cities, including New York City. The faster they can protect people, the lower the effects of economic shutdown and the fewer people will be on ventilators and other life support.
In normal vaccine trials, Nature’s Ewen Calloway notes, scientists give thousands of people either a vaccine or placebo and then track them as they go about their lives, to see if those who received the potential vaccine contract the disease. “A quicker option would be to conduct a ‘human challenge’ study, argue scientists in a provocative preprint published this week,” Calloway notes. “This would involve exposing perhaps 100 healthy young people to the virus and seeing whether those who get the vaccine escape infection.”
Calloway interviews the lead author of the pending journal article suggesting this approach, Nir Eyal, the director of the Center for Population-Level Bioethics at Rutgers University.
“Are there any precedents for infecting healthy people with a pathogen?” Calloway asks.
“We do human-challenge studies for less deadly diseases quite frequently,” Eyal answers. “For example, for influenza, typhoid, cholera and malaria. There are some historical precedents for exposure to very deadly viruses. The thing that demarcates the design that we propose from some of these historical instances is that we feel there is a way to make these trials surprisingly safe.”
“The dramatic-sounding exposure of healthy volunteers to the virus is therefore adding less net risk than you might think,” Eyal told Calloway, after noting that volunteers would be low-risk for the worst coronavirus outcomes by being healthy, between the ages of 20 and 45, and given superb medical care. “It might even be curiously safer for some to join the study than to await probable infection and then try to rely on the general health-care system.”
Eyal’s coauthors are Marc Lipsitch, a professor of epidemiology with a joint appointment in the Department of Immunology and Infectious Diseases at Harvard University’s school of public health; and Peter G. Smith, a professor of tropical epidemiology and former head of the epidemiology department at the London School of Hygiene and Tropical Medicine. The prepublication paper is freely available now through Harvard University.
The paper notes that reducing massive global death tolls “will probably depend on the development of effective vaccines that could be rolled out widely.” Yet current estimates suggest that is not going to happen for another 12-18 months.
Much of that delay is due to the usual testing of vaccines through placebo-controlled trials, “which typically involve several thousand participants followed for long enough in the field to assess differences in disease incidence between vaccine and control groups, with many participants taking precautions to avoid exposure,” the paper says. The authors then contend that “controlled human challenge studies,” or volunteers deliberately allowing themselves to be infected with coronavirus, could help save thousands if not hundreds of thousands of lives by speeding the vaccine process.
“[V]accines could be our soceities’ [sic] only way out of the bind between economic stagnation and widespread mortality,” Eyal noted. “…Do I believe that countries will jump on board? Judging from the response we are getting from various stakeholders since publishing the preprint, I believe that many will.”