I guess a better way of putting that is that R0 is fixed for a particular population but humans are composed of many different populations, just like there are other populations of different species a virus can also infect which might have their own R0s as well.
I guess a better way of putting that is that R0 is fixed for a particular population but humans are composed of many different populations, just like there are other populations of different species a virus can also infect which might have their own R0s as well.