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It's been mentioned to me in the discussion on another question that the following proposal has been advanced (in a medical journal):

Controlled human challenge trials of SARS-CoV-2 vaccine candidates could accelerate the testing and potential rollout of efficacious vaccines. By replacing conventional Phase 3 testing of vaccine candidates, such trials may subtract many months from the licensure process, making efficacious vaccines available more quickly. Obviously, challenging volunteers with this live virus risks inducing severe disease and possibly even death. However, we argue that such studies, by accelerating vaccine evaluation, could reduce the global burden of coronavirus-related mortality and morbidity. Volunteers in such studies could autonomously authorize the risks to themselves, and their net risk could be acceptable if participants comprise healthy young adults, who are at relatively low risk of serious disease following natural infection, they have a high baseline risk of natural infection, and during the trial they receive frequent monitoring and, following any infection, the best available care.

(Perhaps even more notably, the lead author of that paper was interviewed at length in Nature on the topic. But no 3rd party reactions to the proposal were included. A somewhat skeptical reaction by a French bioethicist was published by France24 (in French).)

Have any regulatory agencies (FDA or equivalents elsewhere) reacted positively to such a proposal?

the gods from engineering
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  • https://www.timeslive.co.za/sport/soccer/2020-04-04-drogba-joins-row-after-french-scientists-suggest-testing-virus-vaccine-in-africa/ – Graham Chiu Apr 07 '20 at 23:59
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    @GrahamChiu: I've read that article pretty carefully, but I don't see how it's relevant to my question. Drug trials being nowadays conducted in somewhat hush-hush manner in 3rd world countries is one thing (ans somewhat common). I don't see though where they discuss a live Covid-19 challenge for the (African) test subjects in there. (Maybe you are assuming they would do it?) – the gods from engineering Apr 08 '20 at 04:23
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    Yeah, history shows prisoners etc were used for testing. I'd imagine if you were a leader of a very poor country it might seem attractive to you rather than lose millions to the virus – Graham Chiu Apr 08 '20 at 04:30
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    However, there are trials of hydroxychloroquine amongst medical staff to see if it protects them so that's similar but refers to inadvertent exposure – Graham Chiu Apr 08 '20 at 05:22
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    There's now a website looking for volunteers: https://www.thecovidchallenge.org/ - presumably hoping that it would soon be allowed. I've signed up today. – JonathanReez Apr 09 '20 at 02:16
  • Sadly still no progress on this extremely important experiment. We're living in a failed regulatory state, it seems. What a disaster. – JonathanReez Jun 01 '20 at 06:05
  • @JonathanReez I think calling it a "failed regulatory state" is an overstatement. You can't just rush into human challenge studies with a new disease we know almost nothing about that's killing millions of people. – Carey Gregory Nov 10 '22 at 02:24
  • @CareyGregory um… yeah you can. It was a complete no-brainer as early as February 2020 when we knew the virus doesn’t kill young, healthy people. In fact we did rush to develop new vaccines and treatments but unfortunately didn’t do vaccine challenge trials on time. And I have skin in the game here - I personally volunteered to be a part of the trial and was willing to lose my life for the sake of the experiment. Tens of thousands of people like me signed up as well. I did get to participate in a vaccine study but it wasn’t a challenge trial unfortunately. – JonathanReez Nov 10 '22 at 02:37
  • @JonathanReez We knew nothing of the sort. It does kill young, healthy people. Not as often, but that's the best you can say about it. – Carey Gregory Nov 10 '22 at 04:50
  • @CareyGregory for the sake of argument let's say it kills 1% of young people who apply for the trial. Why is that a reason to prevent able-bodied volunteers to agree to participate in a challenge trial? It makes zero sense. I was more than willing to do it in March 2020 and I'm still upset I didn't get a chance. – JonathanReez Nov 10 '22 at 04:56
  • @JonathanReez I think it's great that you and others were willing to risk death for the greater good, but that doesn't make it ethical for researchers to accept your offer. And did lack of such a trial actually delay the vaccines much? I don't know that it did. I get what you're saying but I just think "We're living in a failed regulatory state" is hyperbole. – Carey Gregory Nov 10 '22 at 05:17
  • @CareyGregory I struggle to understand why it wouldn’t be ethical to accept the offer, assuming all volunteers are not receiving remuneration and can be shown to be mentally stable. And even if it might be unethical for certain schools of thought I don’t understand why the government should meddle and make such experiments illegal. Vaccines have indeed been delayed by the lack of challenge trials - we could’ve known whether or not every single vaccine candidate works in ~1 month vs the 8 months it actually took for the first approval to happen. – JonathanReez Nov 10 '22 at 05:24

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A human challenge trial ended up happening in the UK in late 2021, though it didn't examine the effectiveness of vaccines:

The UK study of 34 individuals, aged 18–30 years, shows that such trials can be done safely, say scientists, and lays the groundwork for more in-depth studies of vaccines, antivirals and immune responses to SARS-CoV-2 infection. The results were posted1 on 1 February on the preprint server Research Square and have not been peer reviewed.

Nearly half of the participants who received a low dose of virus did not become infected, and some of those who became infected had no symptoms. Participants who did develop COVID-19 reported mild-to-moderate symptoms, including sore throats, runny noses and loss of smell and taste.

Unfortunately it doesn't seem like there's any other human challenge trials in the works.

JonathanReez
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  • Tiny study, barely meets statistical minimums. I don't think I'd put a lot of credence in it since there have been deaths associated with COVID among people in that age group and younger. And notice how much they had to pay the volunteers. Who's going to fund a larger study that has to pay participants thousands of dollars? – Carey Gregory Nov 10 '22 at 02:21
  • @CareyGregory there were hundreds of wealthy people willing to fund such a trial back in 2020, the only barrier was regulatory approval. Lookup 1DaySooner - myself and tens of thousands of others signed up to do such a trial free of charge. If I had a chance to participate in the UK challenge trial I would’ve happily done so free of charge. – JonathanReez Nov 10 '22 at 02:39