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> I have to say, I cannot understand why the idea of doing a challenge trial is controversial. If you are using healthy, young, volunteers who are observed and

> I have to say, I cannot understand why the idea of doing a challenge trial is controversial. If you are using healthy, young, volunteers who are observed and have good access to medical care, how could it be unethical? I think the most prelevant is COVID-19, at full strength, still kills seemingly healthy young people. The author mentions this in another article: > The important question we have to consider is if it is ethical to deliberately expose even the young and healthy to the dangerous SARS-CoV-2 virus when we know it could seriously injure or kill them.[0] In this article, we potentially have a weaker strains on our hands that could qualify as a fully ethical challenge trial that could accelerate the development. At the end of the day, challenge trials are Phase trials with less restrictions in hopes of trading accuracy/rigor for speed. Is it worth it? I don't know. I'm not knowledgeable enough to say one way or another. [0] https://www.tillett.info/2020/04/24/it-is-unethical-to-not-search-for-an-attenuated-sars-cov-2-strain/ https://www.tillett.info/2020/04/24/it-is-unethical-to-not-s...

cameldrv 7y ago
If you can use a weaker strain and presumably get the same results, of course, pick the safer option. However, if you can't, and people of sound mind are volunteering for noble reasons, why wouldn't we do that? Is it worth it? We've lost about 200,000 people worldwide just in the past month from this disease. It's the leading cause of death in many countries. In healthy young people (20s, no preexisting conditions), the fatality rate is well under 0.1%. If the vaccine doesn't work at all, which is unlikely, you'd expect 0-1 deaths from the trial. To save perhaps a single life of a willing, altruistic volunteer subject while hundreds of thousands die every month, and the world is confined to its homes is to me, utter insanity. Do we tell firefighters to not go into a burning building to save lives, even if there is considerable risk? If this is the state of medical ethics, the field should be torn down and rebuilt. To deny approval for a challenge trial with volunteers is mass murder.
- roenxi 7y ago
  Yes; but the explanation is unfortunately modern medical ethics is misnamed. The focus isn't on ethics, but on protecting the ethics board from accusations that they directly allowed someone to die or suffer. The process is similar for most forms of regulation. The equilibrium is where no accident can be pinned on the regulators rather than on any sort of system-wide optimum. It can be very frustrating to deal with.
- irjustin 7y ago
  I've just learned in my thread above with the article author that there is no concept of exposing people post vaccination Phase II or III to see if it was effective. We normally wait a long time to see if people get sick. If it's effective them we go to mass rollout. That's where the huge time savings is. My previous statement of "it's a Phase trial with less restrictions" isn't true. It's making the feedback loop tighter. With this new knowledge, I'm relatively convinced we should be doing a challenge trial to speed up the roll out.
  - danieltillett 7y ago
    There is a concept of using a challenge trial, only it can only be used when the risk to the volunteer is very low. Challenge trial are used in trials on things like the common cold. SARS-CoV-2 is considered too dangerous to use in a challenge trial.
  - cameldrv 7y ago
    This is a great point. In order to get statistical significance, you need to subject the same number of people to the virus. In a non-challenge trial, we feel better about ourselves because the challenge is "natural", the subjects would have been exposed to it anyhow. In a challenge trial, you deliberately expose them. Either way, roughly the same number of people will be exposed to the virus. Meanwhile, maybe 1,000,000 people a day are catching COVID. The bottleneck that stops that from continuing every single day involves some risk (if the vaccine doesn't work), of a few hundred people, who are in the most favorable position if they catch it, who volunteered. "Better 1,000,000 people die from COVID than one person die that tried to stop it."

cameldrv 7y ago

If you can use a weaker strain and presumably get the same results, of course, pick the safer option. However, if you can't, and people of sound mind are volunteering for noble reasons, why wouldn't we do that? Is it worth it? We've lost about 200,000 people worldwide just in the past month from this disease. It's the leading cause of death in many countries. In healthy young people (20s, no preexisting conditions), the fatality rate is well under 0.1%. If the vaccine doesn't work at all, which is unlikely, you'd expect 0-1 deaths from the trial. To save perhaps a single life of a willing, altruistic volunteer subject while hundreds of thousands die every month, and the world is confined to its homes is to me, utter insanity. Do we tell firefighters to not go into a burning building to save lives, even if there is considerable risk? If this is the state of medical ethics, the field should be torn down and rebuilt. To deny approval for a challenge trial with volunteers is mass murder.

roenxi 7y ago
Yes; but the explanation is unfortunately modern medical ethics is misnamed. The focus isn't on ethics, but on protecting the ethics board from accusations that they directly allowed someone to die or suffer. The process is similar for most forms of regulation. The equilibrium is where no accident can be pinned on the regulators rather than on any sort of system-wide optimum. It can be very frustrating to deal with.
irjustin 7y ago
I've just learned in my thread above with the article author that there is no concept of exposing people post vaccination Phase II or III to see if it was effective. We normally wait a long time to see if people get sick. If it's effective them we go to mass rollout. That's where the huge time savings is. My previous statement of "it's a Phase trial with less restrictions" isn't true. It's making the feedback loop tighter. With this new knowledge, I'm relatively convinced we should be doing a challenge trial to speed up the roll out.
- danieltillett 7y ago
  There is a concept of using a challenge trial, only it can only be used when the risk to the volunteer is very low. Challenge trial are used in trials on things like the common cold. SARS-CoV-2 is considered too dangerous to use in a challenge trial.
- cameldrv 7y ago
  This is a great point. In order to get statistical significance, you need to subject the same number of people to the virus. In a non-challenge trial, we feel better about ourselves because the challenge is "natural", the subjects would have been exposed to it anyhow. In a challenge trial, you deliberately expose them. Either way, roughly the same number of people will be exposed to the virus. Meanwhile, maybe 1,000,000 people a day are catching COVID. The bottleneck that stops that from continuing every single day involves some risk (if the vaccine doesn't work), of a few hundred people, who are in the most favorable position if they catch it, who volunteered. "Better 1,000,000 people die from COVID than one person die that tried to stop it."