Hence, given the well-known correlation between COVID-19 and, respectively, thyroid gland involvement on one side and increased platelet function on the other side, since the relationship between the latter two is still discussed, by means of a retrospective study on patients hospitalized for COVID-19 without known thyroid diseases, we hypothesized a possible association between TH levels and MPV values parallel to COVID-19 severity. This evidence concerns the gene TH and COVID-19.