That's useful, thanks. Though an estimate of seroprevalence based on a blood bank survey (both of these are from the same group, using the same method) has issu

That's useful, thanks. Though an estimate of seroprevalence based on a blood bank survey (both of these are from the same group, using the same method) has issues with bias (in particular, see the number of re-weightings performed and the huge impact of these adjustments in Figure 2A of the second link), that makes me hesitant to believe any claim starting with "75% of the population was infected, therefore..." In other words: if we're seeing a resurgence in cases now, the parsimonious answer is that the blood-bank survey estimate was wrong, not that the virus is escaping all immunity. My prior probability of this explanation is dramatically increased when I see that the seroprevalence data was adjusted upward by a factor of 2-3 to account for "seroreversion" (which is essentially guessing).