Why is the US different?
In the larger countries of Western Europe the scale of death tolls has varied significantly, but the shape of the mortality curve has not. In most of Western Europe, covid-19 deaths have risen and fallen around a single peak in a familiar bell-shaped curve.
As shown in the above image, covid-19 mortality curves for Europe are very similar to the curve predicted by the so-called ‘SIR Model’. SIR, developed by Scottish scientists Kermack and McKendrick in the 1920s and 1930s, is a mathematical model used to predict the path of a number of different infectious diseases.  Notice how the curve rises slightly more steeply than it declines in both the SIR model and the covid data. The similarity between this decades-old mathematical model and 2020 covid mortality curves is striking. This observation suggests a natural process and not one resulting mainly from human interventions.
Notice however that the US covid-19 mortality curve does not follow the pattern of these European countries and by extension the SIR model. Why is the US different?
— Lees op inproportion2.talkigy.com/us_regions_climate_covid_6sep.html