[rallison]

The fundamental issue I see in the piece is a conflation of what herd immunity means. Normally, it's used in the context of normal activity levels - as in, if everyone went back to normal pre-pandemic routines, would we see cases go up or down? But, you're using it in the context of current activity levels, which are still significantly different than pre-pandemic activity levels.

All you are effectively saying is that, given the current mitigation measures and given the current level of population immunity, R is less than 1 in these places. But, that's not really a revelation.

What one would expect is likely to be the case is that some areas have had enough exposure that it has a non-zero impact on their current R, as in NY and NJ. This means there may be more buffer to relax mitigation measures without seeing R rise above 1, but it doesn't necessarily mean they are at herd immunity.