Is the Sars-CoV-2 epidemic losing its virulence? Opinions and looking for evidence

Abstract

Several experts - mostly in Italy, and later in Spain too - have in the last few weeks shared publicly their opinion that possibly Sars-CoV-2 might be becoming less virulent, at least in those regions and at the present moment. It is important to verify to what extent such expert opinions reflect levels of testable evidence, beyond personal impressions. In this paper we try, first, to report on those opinions; second to review the arguments that could support them; and third to look for empirical evidence through the statistical analysis of official records, trying to specify indexes of severity and their evolution since the pandemic peaked. The available data do not allow for a robust conclusion, but neither exclude that possibility: the epidemic could be weakening; but only time and more research will settle this issue.