Only one number that matters, the current / effective reproduction number [e.g. 0]. Everything else is a consequence of that. Deaths within cohort are decreasi

Only one number that matters, the current / effective reproduction number [e.g. 0]. Everything else is a consequence of that. Deaths within cohort are decreasing because of increasingly effective treatment options [1]. The medical system works a lot like our adaptive immune system when faced with a novel pathogen, and it takes some time for best practices to be discovered and promulgated. Even symptom treatment is going to seriously decrease all-cause mortality. Having volunteered at a large US metro board of health over the last two months, booking testing appointments and arranging result reporting, I can tell you that a substantial number of under-50s are being testing. Primarily families and people with exposure to a known case. Effectively, there are a few groups the virus spreads through: (Won't shelter)|(Can't shelter) + (Won't protect)|(Can't protect) + (Will protect) + (Will shelter). The spikes we're seeing are a consequence of public health policy + current SEIR proportions in those various groups. As more vulnerable groups are increasingly infected, they become immune (aka recovered), which decreases the ability the virus to transmit in those groups. And left with less vulnerable groups of susceptible individuals, effective reproductive number decreases. The danger of SARS-CoV-2, given the relatively low mortality (and based on genetic modeling of potential mutations), was never that it was going to crest with Ebola-like proportions (you get it, you die), but that it was going to crest with a magnitude that would overwhelm available medical resources. Unfortunately, that crest is a binary proposition: either you have spare medical capacity (and serious Covid-19 patients receive high-quality care) or you have none (and serious Covid-19 patients receive no treatment). So the danger is not death rates now. The danger is (effective reproductive number) -> (expected case count) -> (serious, hospitalized cases of Covid-19) -> (exhausted medical capacity) -> (Italy-esque spike in deaths). [0] https://rt.live/ https://rt.live/ [1] https://blogs.sciencemag.org/pipeline/archives/2020/06/17/dexamethasone-for-coronavirus-infection https://blogs.sciencemag.org/pipeline/archives/2020/06/17/de... [2] https://blogs.sciencemag.org/pipeline/archives/2020/05/15/good-news-on-the-human-immune-response-to-the-coronavirus https://blogs.sciencemag.org/pipeline/archives/2020/05/15/go...