HMOX1 and COVID-19: The suppression of oxidative stress is also a potential strategy for the treatment of COVID-19, and our previous study demonstrated the induction of nuclear factor-erythroid 2-related factor 2 (Nrf2), a master regulator of antioxidant responses, such as heme oxygenase-1 (HO-1), superoxide dismutase 1 (SOD1) and SOD2, by phototherapy with full-spectrum light [41].