[mchusma]

Does anyone know if there have been any serious human challenge proposals considered? Why they aren't being considered is one of the biggest puzzles for me.

[mleonhard]

WHO is working on human challenge trials for covid-19 vaccines. Links from Wikipedia:

https://apps.who.int/iris/bitstream/handle/10665/331976/WHO-...

https://www.sciencemag.org/news/2020/03/speed-coronavirus-va...