Since RAAS inhibitors such as angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARBs) may increase the expression of ACE2 in type 2 alveolar epithelial cells in the lungs due to upregulation, the concern was raised that these medications could increase the risk of developing a more severe form of COVID-19, enhancing the susceptibility to viral entry through ACE2 binding of SARS-CoV-2. Here, ACE2 is linked to COVID-19.