ACE2 and COVID-19: In contrast with ACE2-modulating medications, we have offered the hypothesis that DPP-4 inhibitors act in prevention/treatment of pulmonary fibrosis, heart, and kidney injury, and since they may be a long-term consequence caused by COVID-19, it is reasonable to expect that DPP-4 inhibitors might be beneficial in alleviating long-term consequences of COVID-19.