To those who find this exercise distasteful (yet hang on the daily tracker numbers slavishly, and often throw around about how there will be millions dead), well, don’t participate. To me having a sense of how bad this is going to end up being by this metric is very important. And appreciating the lack of key information to the degree that the most expert minds are coming up with predictions of such wide ranges is also important to highlight.
RivkahChaya, we could get a vaccine, but not likely one that will available before the end of 2020. 12 months is optimistic, 18 months more realistic.
Addressing Carryon and Musicat’s comments.
My stab at it was not using a formula at all, but looking at the log scale deaths/million “growth charts” on the linked cite. There is a common shape to those growth charts (reflective of both natural history of the disease in the populations and of the timing of the Western world’s publics’ and governments’ responses to it). The curves originate at 1 death/million population and all of Italy, Spain, and France, are farther along on the curve from that point than we are. They all show the log curve beginning to get less steep around day 10 to 15 days into the curve. Projecting the Italy and Spain curves (farthest along of the bigger number counties) current trajectories have them both likely becoming flat at around 250 deaths/million.
I think that just as it reasonable to use previous children’s growth to predict the adult height of a 2 year old, it is reasonable for us at day six from hitting that mark to use the growth trajectory of those ahead of us to make an estimate of what we will see. Yes it will not be exact just as few children follow the standard curves exactly (impacted by demographics and responses/capacity specific to each nation), but a good rough stab. (250 deaths/million) * (population of the United States) 330 million = 82,500. Those who predict many more times than that are predicting that we will have that many more times the deaths per million population than Italy, France, or Spain look to be on course to have.
Now it could be that my extrapolation of those curves is faulty, and that they do not continue to flatten any more than they have but stay at this lower rate for months, more gradually but consistently increasing over months, or even jumping up as restrictions are lifted. We do not know for sure that Italy’s deaths/million are actually closing in on adult height.
But yes using the SIR type of model is fraught right now as it is so dependent on what is input into it as assumptions. My prediction based on those growth curves is consistent with what I calculate using assumptions of 1% fatality rate among those symptomatic enough to be labelled as having COVID-19, 8 to 9 others who get infected with SARS-CoV-2 but remain either asymptomatic or so mildly symptomatic as to never be labelled as having COVID-19, children mostly non-contagious, and herd immunity beginning to play a factor at an infection rate of 40% with bigger impact at 50%. How valid or invalid are those assumptions? They are not crazy ones but …? The fact that we don’t have some better harder basis for which assumptions are most valid is hard to excuse. Given that lack I’m thinking the growth chart analogy approach is the best roadmap approach for now. IMHO.