Incidentally, ascorbic acid (vitamin C) and the bioflavonoid quercetin (originally labeled vitamin P) were both discovered by the same scientist — Nobel prize winner Albert Szent-Györgyi.4,5 Quercetin's antiviral capacity has been attributed to five main mechanisms of action:

Inhibiting the virus' ability to infect cells by transporting zinc across cellular membranes

Inhibiting replication of already infected cells

Reducing infected cells' resistance to treatment with antiviral medication

Inhibiting platelet aggregation — and many COVID-19 patients suffer abnormal blood clotting

Promoting SIRT2, thereby inhibiting the NLRP3 inflammasome assembly involved with COVID-19 infection

Similarly, vitamin C at extremely high doses also acts as an antiviral drug, effectively inactivating viruses. During the 2003 SARS pandemic, a Finnish researcher called6 for an investigation into the use of vitamin C after research showed it not only protected broiler chicks against avian coronavirus, but also cut the duration and severity of common cold in humans and significantly lowered susceptibility to pneumonia.