Coronavirus vaccine trials on healthy human are dangerous but hold immense value, say experts
The coronavirus pandemic has the world moving at record speeds to develop a vaccine. Even then, some experts think the virus will most likely stay far ahead of us - unless we adopt a controversial measure: human challenge trials.
And now, the World Health Organization (WHO) is also supporting the cause, but with conditions. Traditionally, vaccines take 10-15 years to develop but coronavirus shots may arrive in 18 months, which is still too far away.
Human challenge trials, emerged into the spotlight in late March, to speed up vaccine testing. The bold approach requires participation from young and healthy volunteers. Once they sign up, health officials will inject them with a potential vaccine and then infect them with the new coronavirus. This could replace the traditional practice of waiting for the virus to strike vaccinated individuals.
The potential vaccine will pass muster if it manages to protect a majority of human challenge volunteers from Covid-19. These studies have come in handy against diseases such as smallpox, yellow fever, and malaria. The idea has since gathered steam. Nearly 14,183 adults from 102 countries are willing to volunteer for such trails, according to 1Day Sooner, a grassroots group of scientists and researchers.
But these trials can be dangerous: some Covid-19 victims are young people. Since there is no cure, deliberately infecting the young is unethical, say some experts.
"If we knew more about the serious risks from COVID-19: why some young, healthy people can get very sick; or how to treat the disease to prevent serious complications, a human challenge study with the novel coronavirus would be much safer and easier to justify," Seema Shah, JD, Associate Professor of Pediatrics and Founder’s Board Professor of Medical Ethics at Lurie Children’s Hospital/Northwestern University, tells MEA WorldWide (MEAWW).
Human challenge studies might be late already
Initially, experts proposed human challenge studies to replace a step in the vaccine development process. But a couple of vaccines have already entered clinical trials.
Human challenge studies are falling behind because they could take six months to a year to set up. "It is possible that the train has already left the station," Shah adds.
But they can still have numerous applications. "It can help pick the best of a few different vaccine or treatment candidates for further testing or set up manufacturing early. It can tell us more about whether vaccines could themselves cause harm, or identify a way to tell when someone has immunity against the novel coronavirus," she explains.
How can experts make them safe?
Experts are now drawing up plans to make these studies more safe and ethical. The WHO has also come up with a list of guidelines.
“The big news is that WHO doesn’t say challenge trials are forbidden. It specifies reasonable steps on how they can be deployed,” Prof Nir Eyal, the director of Rutgers University’s Center for Population-Level Bioethics, tells The Guardian.
In their study, Shah and her team call for fairly selecting participants and getting their informed consent while also compensating them appropriately.
Experts will also have to decide on an appropriate dose of the new coronavirus. It should be enough to cause illness, but not a severe one.
Other experts think we need more data before adopting these studies. “I don’t think I would always be a ‘no’ for a human challenge model. But I think right now we do not have the data we need to proceed in a safe and ethical way," Beth Kirkpatrick, who runs a human challenge trials unit at the University of Vermont, where she is chair of the department of microbiology and molecular genetics, tells STAT.
But, according to Shah, it is a good idea to set up an ethical framework now. "Even though challenge studies can be controversial, there is good reason to start laying the groundwork for conducting challenge studies with the novel coronavirus," she says.