Inhaled Nitric Oxide for postexposure chemoprophylaxis of COVID-19

Background: Postexposure prophylaxis has been an overlooked strategy in the context of COVID-19. Inhaled Nitric Oxide offers itself as a potential tool in this context. The aim of this systematic review was to depict previous in vivo and in vitro studies demonstrating an antiviral role for NO Methodology: Embase, Medline and the Cochrane Central Register were used to search for specific keywords such as “Nitric oxide” AND “Antiviral activity” for relevant publications up to 1 st of June 2021. The systematic review was performed using PRISMA protocol Results: Twenty-one studies were identified depicting an antiviral role for Nitric Oxide. Those studies involved sixteen viruses. Only four of the depicted studies were clinical trials, while three were performed on a murine model. The remainder of the studies involved in vitro experimentation of the role of NO in halting viral replication of several viruses including SARS-CoV-2 Conclusion: While early reports of NO role in the treatment of COVID-19 suggested its use for the treatment of established ARDS, NO seems to have a much earlier and more efficient prophylactic role. It inhibits a protease needed for canonical viral replication of SARS-CoV-2, namely Furin, by decreasing calcium's cytosolic levels. This might add a significant tool for postexposure chemoprophylaxis in the at-risk group, especially medical personnel.