NOS2 and COVID-19: Interestingly, upon exposure to SARS-CoV-2, the activation of inducible Nitric Oxide Synthase (iNOS), an important biological mediator of inflammation and immunoregulation producing Nitric Oxide (NO) from L-arginine, causes an overproduction of the superoxide radical ion (O2−) in people who have survived the acute phase of COVID-19 that becomes self-perpetuating, even when the virus has been cleared, turning into a persistent and protracted free radical-induced damage [154].