This article provides an excellent overview of the history of the disease at the beginning and then examines what makes SARS-cov-2 deadly among some persons. Nitty gritty medical journal language to be expected: this is serious stuff that they want to get as exact as possible. To be a good point of comparison with Fleck. Written when the number of deaths globally was 2,858; the global number of confirmed cases stood at 83,652.
