COVID-19 Statistics

COVID-19 is a dangerous pandemic that has thus far been responsible for approximately 70,000 deaths worldwide.  The USA, most European countries, China, South Korea, India and Japan have all instituted restrictions on social interactions and economic activity that will likely precipitate a global recession but these measures appear to be having a significant impact on the spread of the virus. Much of the reporting on on the pandemic focuses on irrelevant or difficult to interpret statistics. The number of diagnosed cases is a frequently reported statistic that conveys little information without being given more context.  The number of diagnosed cases is very dependent on the number of tests that are performed in a specific population (county, city, state, country). For example, on April 10 the total number of diagnosed cases was similar in France in Germany (approximately 125,000) which might lead one to conclude that disease severity is similar in both countries. However, the rate of testing (tests/million of population) was three time higher in Germany than in France. If one really wants to know the severity of the disease in a particular country then the number of deaths is a much more informative statistic; by April 10 the total number of deaths in France stood at 13,832 compared to a total of 2871 in Germany. Clearly the disease is much more severe in France than in Germany but the total number of diagosed cases in each country gives no indication of this fact.  Another frequently reported statistic is the number of recovered cases which is again virtually impossible to interpret for a disease that in most infected persons causes mild or no noticeable symptoms.  The recovered cases are those who were admitted to hospital because of the disease and eventually discharged. It is depenent on the number of hospital beds, on the overall occupancy of the hospital beds, on the criteria for hospital admission, and on the quality of medical care. For this particular disease, the only statistic that unequivocally describes the severity is the number of deaths and this is the number we should focus on.