Similar to SARS (severe acute respiratory syndrome, 2002–2003) coronavirus (SARS-CoV) [3], SARS-CoV-2 primarily uses the S protein to invade host cells through ACE2, an enzyme which is known to be important in the renin–angiotensin–aldosterone system (RAAS) [4,5]. This evidence concerns the gene ACE2 and severe acute respiratory syndrome.