They’re using 1 minus the hazard ratio, the reduction in the proportion of not yet infected people who are infected at any given time. That is, an 80% efficacy would would that if x% of unvaccinated and as yet uninfected people were infected at some time then (1-0.8)x% of vaccinated and as yet uninfected people would be.
The advantage here is that the proportion of people infected would (unless your vaccine is perfect) eventually go to 100% in both groups, so how long you follow them up for will matter a lot.
They’re using 1 minus the hazard ratio, the reduction in the proportion of not yet infected people who are infected at any given time. That is, an 80% efficacy would would that if x% of unvaccinated and as yet uninfected people were infected at some time then (1-0.8)x% of vaccinated and as yet uninfected people would be.
The advantage here is that the proportion of people infected would (unless your vaccine is perfect) eventually go to 100% in both groups, so how long you follow them up for will matter a lot.
Nice, that helped clear this up for me!
I think there is a typo here:
Should say:
Right?
(else I’m still confused, heh.)
Yes, thank you for the correction