I think there is little doubt that the herd immunity threshold is likely to be in the 20-30% range but all this really tells us is that in some parts of the country we are at a stage where it's unlikely that an individual cluster of cases is unlikely to lead to a chain of cases..

that could affect the whole country not what can happen within different parts of the community. More importantly you always get an overshoot that is bigger than the figure that is calculated for HIT and in general the lower the figure the higher the overshoot.

This is exacerbated with covid-19 as it is obviously able to still spread around and percolate and bubble through society even at low levels.

So I would say for many questions herd immunity is irrelevant - it's the actual immunity which is more pertinent -

that is why we will not see any sustained exponential growth except on localised levels.