And it seems from the hostility of your response ("delete the comment as misinformation") that you find it incredible that herd immunity could exist with less than 1 - 1/R0 of the population infected? But even ignoring any pre-existing immunity, that calculation assumes a homogeneous and well-mixed population. That's clearly not the case, since some people (a nurse in a crowded ER, a police officer, a store clerk, a nightlife enthusiast, etc.) have far more contacts than others (a remote worker who gets stuff delivered). People with more contacts will get infected first, with disproportionate harm, and then become immune first, with disproportionate benefit. Many papers have modeled[2] this; though no one's found a great way to measure that heterogeneity yet, so for now, it's hard to say much beyond that the effect exists, and is potentially big.
And finally, herd immunity isn't a binary threshold, especially in a heterogeneous population. As others have noted, even places without enough immunity for R < 1 will still have slower spread than in a naive population, or may get to R < 1 from the immunity plus slightly more cautious behavior. Conversely, places that do have R < 1 overall may still have pockets of spread in sub-populations with unusually high R0. In any case, it's no conspiracy theory to believe that NYC developed significant amounts of immunity along the way to its ~24k (about 0.3% of the population!) deaths.
1. https://www.nature.com/articles/s41586-020-2550-z
2. https://www.medrxiv.org/content/10.1101/2020.02.10.20021725v...
I would suggest in future supplying this to the conversation yourself as it makes for a more productive discussion.
[1] https://www.nih.gov/news-events/nih-research-matters/immune-...
Can't comment on the other stuff.
