Nitric Oxide to Fight Viral Infections

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that has quickly and deeply affected the world, with over 60 million confirmed cases There has been a great effort worldwide to contain the virus and to search for an effective treatment for patients who become critically ill with COVID-19 A promising therapeutic compound currently undergoing clinical trials for COVID-19 is nitric oxide (NO), which is a free radical that has been previously reported to inhibit the replication of several DNA and RNA viruses, including coronaviruses Although NO has potent antiviral activity, it has a complex role in the immunological host responses to viral infections, i e , it can be essential for pathogen control or detrimental for the host, depending on its concentration and the type of virus In this Essay, the antiviral role of NO against SARS-CoV, SARS-CoV-2, and other human viruses is highlighted, current development of NO-based therapies used in the clinic is summarized, existing challenges are discussed and possible further developments of NO to fight viral infections are suggested © 2021 The Authors Advanced Science published by Wiley-VCH GmbH