This is indeed a thoughtful take on #challengetrials for coronavirus vaccine development. I have a few thoughts too.
First, appreciate that Nir and @mlipsitch posted this ASAP for the world to see as a preprint. Marc, is it under review?
One big pt seems to be exactly (or approximately) how much time would be cut off vaccine approval if we take this approach. OTOH, even short time off could be impt if we have small # of people in challenge trial (most of whom will be OK) + more people dying each day we wait.
But hard to really know whether challenge trial participants will be OK even if young. We're still learning so much about this virus and how it affects people in unexpected ways.
Marc/Nir propose using challenge trials for Phase 3 efficacy studies (rather than to down-select early vaccine candidates). By that point, we could have some better safety/efficacy data on COVID-19 therapies, which may change the risk calculus for challenge participants.
We still don't know much about how challenge trials for risky diseases could affect public trust. What type of community/public buy-in should we have for these studies - or is individual consent all that's needed?
Overall, I do think it's reasonable to be considering challenge trials for this virus. Risks/benefits could be appropriate with the right protections - but still think we need to know a bit more about each. Perhaps we will by Phase 3.
And BTW, if the risk of a challenge trial here worries you, guess what we're doing to health care workers each day we send them to the front lines without #PPE? Challenge without the trial part.
Apologies, didn't mean to skip over the third author: Peter Smith.
