Deliberately infecting patients with COVID-19 to speed up vaccine? Human challenge trial raises ethical concerns

In the U.S., vaccine trials are stretching toward the finish line, but what if researchers could speed up the process?
SAN FRANCISCO (KGO) -- There are signs that research on a COVID-19 vaccine could be taking a new turn. But there's debate over the strategy and possible ethical concerns.

Across the U.S., coronavirus vaccine trials are stretching toward the finish line, after months of patients receiving vaccines or placebos and then returning home. But what if researchers could speed that process up, by infecting them with the virus deliberately? It's known as a human challenge trial.

"It can actually take a shorter period of time, because you don't have to wait for people to get infected," explained Dr. Yvonne Maldonado, an infectious disease expert at Stanford.

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And now, researchers in the U.K. have begun organizing that country's first human challenge trial for COVID-19. At the same time, a movement has also been building in the U.S. Rep. Bill Foster of Illinois co-authored a letter to Health and Human Services and the Food and Drug Administration asking them to consider challenge trials to speed up vaccine development.

"Scientifically It's much more controlled than the large trials where you get 30,000 people and give half the vaccine, half a dummy vaccine, then just wait for months," Foster argued.

Examples of the alternative date back more than century, when an English doctor successfully tested his own rudimentary vaccine for small pox on an 8-year-old boy by deliberately exposing him to the disease. And limited challenge trials are used with some flu vaccines. But the possibility of making someone sick with a dangerous virus there's no cure for raises potential ethical issues for some Bay Area researchers.

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"We don't know how much virus to give people, or whether it's enough or too much. Whether giving them virus is different than how they naturally acquire the virus," said Dr. Maldonado.
Another Stanford colleague, Dr. Phil Grant, believes there are ethical lines when dealing with a virus as new as COVID-19.

"For me even if participants were willing to undergo challenge, that would go beyond what I would consider a reasonable risk," said Dr. Grant.

But supporters argue that new coronavirus treatments like the monoclonal antibody drug given to President Donald Trump are evidence of a changing landscape that could make a challenge trial safer. And with standard trials advancing or nearing completion, supporters believe smaller challenge trials could help scientists hone in on the most effective vaccines more quickly.

"There's a big difference between deploying a vaccine that's 70% effective and one that is 90 or 95% effective," argued Rep. Foster.


There is currently no word of any official move in the U.S. But several weeks ago, Dr. Anthony Fauci confirmed to sources that government researchers are working on a weakened version of the COVID-19 virus. While Fauci described the work as simply precautionary, experts say a weakened version could be potentially useful, if the U.S. ultimately does decide to move ahead with a human challenge trial.



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