Explaining national differences in the mortality of Covid-19: individual patient simulation model to investigate the effects of testing policy and other factors on apparent mortality.

Jonathan A Michaels; Matt D Stevenson

The current Covid-19 pandemic has been the subject of more open and rapid availability of data than any previous disease. This has, inevitably, led to international comparisons of the spread and outcome of the disease, with widespread media speculation regarding the apparent differences in mortality between similar European countries. On the face of it, the differences are stark. On 2 nd April 2020, Germany reported 85,063 confirmed cases with 1,111 deaths (1.3%), whereas three days earlier the comparable figures from Spain had shown 7,716 deaths from 87,956 confirmed cases (8.8%) and three days before that Italy had reported 9,134 deaths from 86,498 cases (10.1%). [1] While these may relate to differences in demographics, treatment or healthcare policy, the apparent mortality may also be altered by differences in testing policy and in changes in the rate of spread brought about by social distancing policies.