Do Challenge Trials Make Sense for COVID-19

[swamidass (S. Joshua Swamidass)]

@sfmatheson

I haven’t seen anyone even attempt to explain the ethical difference between surgically removing someone’s kidney and exposing them to SARS-CoV-2. I think there’s a simple explanation. There isn’t a difference.

I did try once:

@swamidass

There are many differences, and I’ve noted a few here.

1. In clinical studies, the population used has a dramatic effect on results. Challenge trials have a different population than standard trials, which makes them less translatable to practice. In contrast, the kidney donation studies would be using the exact same population of donors in the intended practice.
2. It isn’t possible to imagine a kidney donation trial without kidney donors. It is, in contrast, easy to envision standard trials that would produce the same (perhaps better) information, but just at a slower rate (maybe).
3. Kidney trials match very closely the intended treatment the intend test. Exposure in challenge trials is controlled (which increases statistical power) but we can’t expect them to mimic exposure the virus “in the wild,” which again reduces their translatability.

These are substantial differences from a kidney donor trial. Challenge trials vs. standard trials there is a trade off between the hope of increasing speed and the certainty of reduced translatability. This tradeoff is not part of the kidney donor example, and it may be importnat.

I’m not real sure why you didn’t think this was helpful, but it certainly was an attempt . Perhaps you can clarify by showing us your analysis.