Deliberate infection of healthy volunteers with coronavirus may accelerate vaccine studies against avid, says WHO
Such studies, which present significant potential dangers to subjects, can be considered in extreme situations and with certain disclosures and protections, a working group of the United Nations health agency said in a report published on its website on Wednesday.
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Researchers from around the world are competing to develop vaccines to protect against the deadly coronavirus and allow countries to rebuild wobbly economies. So-called challenge studies, where treatments or preventives are tested directly against infection in informed volunteers, could speed up the path of vaccines to the public.
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Challenge studies “may be substantially faster to perform than vaccine field trials,” according to the working group document, “in part because far fewer participants need to be exposed to experimental vaccines to provide (preliminary) estimates of efficacy. and security. ”
The report set out eight conditions that would have to be met to consider challenge studies, including scientific justification, an assessment of potential benefits, and the subjects’ fully informed consent.
Challenge studies have the potential to reduce coronavirus mortality worldwide, but pose significant potential dangers for volunteers, scientists led by Marc Lipsitch, an epidemiologist at the Harvard School of Public Health, suggested in a recent article.
“Obviously, challenging volunteers with this live virus runs the risk of causing serious illness and possibly even death,” they said in an article in the Journal of Infectious Diseases in March.
Vaccines are generally tested in large groups, and the results are compared to a separate group of unvaccinated people. Waiting for both groups to be exposed to the disease in their normal daily lives can take months, while challenge studies would ensure that subjects were quickly exposed to the virus.
The volunteers would generally be healthy, young adults with a relatively low risk of serious illness, and would be monitored and cared for, the scientists said.
Officials at Moderna Inc., where the lead vaccine for Covid-19 is being developed, are not enthusiastic about the idea.
“I’m not sure I’m a big fan for practical and ethical reasons,” Tal Zaks, medical director of Moderna, said during a presentation by the health news organization Stat on Wednesday. “As is often the case, the devil is in the details.”
Zaks said he was unsure that a challenge study, which could take months to design and implement, would accelerate development of the company’s product, which is already entering the second of three study phases. The injection would have to prevent the development of the disease, not just mild infections, or it would be difficult to know if the chosen dose was correct, he said.
Foundation 1daysooner has a website where people can sign up to participate in a human challenge trial for Covid-19, should one occur. Almost 14,000 volunteers from 102 countries have registered so far.