[cameldrv]

If every single day counted, they would have done challenge trials. What counts is following the FDA's process, and the FDA's process says that you have to administer it in the same way as the trial. No one at the FDA is going to go out on a limb just to save a few thousand lives.

[CyanLite4]

Challenge trials don’t work when 40% of infected are asymptomatic. And challenge trials especially don’t work when 15% of cases require hospitalization and ICU beds are already maxed out.

[cameldrv]

I don't see how the asymptomatic fraction makes a normal trial superior to a challenge trial.

As for the hospitalization and ICU, those numbers are inflated, but regardless, in order to pass the trial, the same number of people need to be infected in the trial. The only difference is that while you're waiting for a few dozen people to be infected naturally because you gave them a placebo, millions are being infected and thousands are dying daily.

[nojito]

I work in healthcare.

Where’s your source on them being inflated?

[MrAlex94]

> Later, a vaccine candidate that has been proven safe in clinical trials could be given to a group of healthy adults in this age range, who are then exposed to the virus in a controlled environment. They would then be closely monitored by medics and researchers to see if the vaccine is successful in preventing infection, as well as identifying any side effects.

> https://www.thelancet.com/journals/lanres/article/PIIS2213-2...

I imagine they will do what they did for the vaccine candidate ChAdOx1 nCoV-2019 and swab at least every week to test for infection.

Do you have any source to back up your claim that a challenge trial wouldn’t work for SARS-CoV-2?

[CyanLite4]

When the asymptomatic rate is high, it’s hard to determine if the vaccine is truly works, and to what degree. If 40% of people are asymptomatic then that would theoretically mean that 40% of challenge trial participants won’t show symptoms. Does that mean the vaccine is working? Who knows. It could be working, it may also not work.

The only way to do it and get real results is to use a challenge trial only on the elderly population where the asymptomatic rate is low and where the symptoms are exaggerated. This would mean though that if the vaccine didn’t work you would overwhelm the hospital system with a lot of sick elderly people who require the most care, when the healthcare system is already overwhelmed.

[bawolff]

What doesn't work about it?

Being ethical and getting results are not the same thing.

[xyzzyz]

Being ethical and being “ethical” according to professional expert ethicists is also not the same thing. If I learned anything this year, it’s that opinion of professional experts at ethics should not be considered when deciding who gets last piece of cake, much less in life and death scenarios.

[cwhiz]

Citation needed for that 15% number. Even if it’s true, it absolutely isn’t true for all age groups. Give to 20-29 year volunteers. There were hundreds of thousands who volunteered.

[rimliu]

What our (Lithuania) officials say is that about 5% of the cases are hospitalized. We are close to the top by the number of new infections per 100000 pop.

[BurningFrog]

Are challenge trials for dearly diseases even legal?