The death rate is NOT a biological constant. It is not fixed to a pathogen. It reflects the severity of the disease in a particular context, at a particular time, in a particular population. The probability that one dies from a disease is not only dependent on the disease itself. 
It also reflects the social AND individual response to it: the level, quality, AND timing of treatment / care they receive, and the ability of the given individual to recover from it. Remember the epidemiological triangle? #epitwitter #scicomm
There are a number of rates, risk, ratios important in an #outbreak. The fatality rates can decrease or increase over time, and that it can vary by location and by the characteristics of the infected population (age, sex, pre-existing conditions). #scicomm #COVID2019 #COVID19
Keep in mind mild cases are under represented in the denominator but time delay until death also artificially lowers the numerator. That's why this new analysis by @C_Althaus et al @ISPMBern accounted for these factors. #COVID19 #SARSCoV2 #epitwitter medrxiv.org/content/10.110…
