TMPRSS2 and COVID-19: However, in COVID-19, The males have been infected more severely than females [50]; the increased mortality in a male might not be because of the viral load, but it may be other reasons: first, the bad habits of males such as smoking and drinking [51]; second, the testosterone in the male has immunosuppressive activity and increases the expression of TMPRSS2 which is the co-receptor for binding SRAS-CoV-2 virus.