Human 'challenge trials' can speed up Covid-19 vaccines and save millions, say Nobel laureates and scientists

They wrote an open letter, urging public health bodies to adopt the approach of deliberately infecting young and healthy volunteers to accelerate vaccines


                            Human 'challenge trials' can speed up Covid-19 vaccines and save millions, say Nobel laureates and scientists
(Getty Images)

More than 100 scientists, including 15 Nobel laureates, have lent their support to a controversial measure that could accelerate the screening of potential coronavirus vaccines — human-challenge trails. They recently wrote an open letter, urging public health bodies to adopt this approach of deliberately infecting young and healthy volunteers to save the lives of millions.

"If challenge trials can safely and effectively speed the vaccine development process, there is a formidable presumption in favor of their use, which would require a very compelling ethical justification to overcome," the scientists wrote in the letter to Dr Francis Collins, director of the US National Institutes of Health (NIH).

Under usual circumstances, experts evaluate vaccines by injecting a dose into participants. They then wait to see if the shot prevents a natural infection in the coming days to pass their verdict. But the problem is that this could take time. With human challenge trials, experts can cut down the waiting period by intentionally infecting the participants. Exposing them to the pathogen under controlled conditions will save time, they added. If a majority of these volunteers do not catch Covid-19, despite being deliberately infected, experts can conclude that a potential vaccine works.

In their letter, they prompted the US government, its allies, international funders and the World Health Organization (WHO) to prepare for human challenge studies, including supporting safe production of the virus and setting up biocontainment facilities for volunteers. They stressed the trials have to recruit young and healthy people to reduce risk. Those aged between 20 and 29 face a risk of death similar to that of kidney donors, they said.

The experts have urged public health bodies to prepare for human challenge studies, including supporting safe production of the virus and setting up biocontainment facilities for volunteers (Getty Images)

"If done properly, live coronavirus human challenge trials can be an important way to accelerate vaccine development and, ideally, to save the lives of millions around the world as well as help rescue global economies," they wrote. Dr Francis Collins, director of NIH, has said Covid-19 challenge trials are "on the table for discussion — not on the table to start designing a plan".

In fact, more than 32,000 volunteers from 140 countries have expressed their interest in participating in such a trial, according to 1Day Sooner, a grassroots group of scientists and researchers. Adrian Hill, director of the Jenner Institute at the University of Oxford in England, reportedly said that the trial had "considerable potential" in helping to accelerate vaccine development and optimize vaccination approaches. Hill has also signed the letter.

But some experts have expressed their reservations, calling it unethical and unsafe. "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, had earlier told MEA WorldWide (MEAWW).

The WHO has also come up with a list of guidelines to make the trials safe and ethical. Experts will also have to hammer out the details such as the appropriate dose of infection — it should be enough to cause illness but not a severe one. "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 added.

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