[sterlind]

People volunteer for military service even during wars, but you're right. Challenge trials won't be brimming with 75-year olds, the same way 75-year olds don't enlist. You'd learn that the vaccine works on healthy 20-somethings though, and that might have been enough for approval.

[andreareina]

Should it be?

[snovv_crash]

If you can prevent 20 and 30 year olds from being infected, you might just manage to halt the spread of the virus even if you don't confer individual immunity onto older people.