They're paying the price of having to be always scared of it lurking undetected. A completely naive population is at greater risk than one which has a buffer of 1-in-20 or 1-in-10 being immune. All it takes is one case (as in that nightclub, made more awkward because it was a gay nightclub and people use fake IDs there due to homophobia) and you have problems.
Remember that graph showing spread, then repeating with "this guy stayed home"? Even a 5% immunity rate means that transmission will be slowed, of the 20 people someone comes into contact with, one now won't transmit it forwards. With a 10% immunity rate, that means two wouldn't transmit it and so on - again, figures are averages here.
The benefit of having these immune folks is that they reduce R over and above of all the other things we're doing... it's like compound interest, it all adds up.
Originally Posted by: Retron