Einar Stefánsson et al.

A natural component of fish oils, free fatty acids (FFA) inactivate enveloped viruses, some bacteria and fungi. We test the hypothesis that free fatty acids made by hydrolysis from fish oil inactivate SARS-CoV-2 in vitro. We also study an existing food additive containing 2% FFA in cod liver oil.

… Cod liver oil and other fish oils naturally contain free fatty acids and have been used as food additives for centuries. 1-2% FFA inactivate SARS-CoV-2 in vitro and are well tolerated in cod liver oil as mouth wash. Widely available in industrial quantities, free fatty acids in fish oil may have potential as mouth/throat wash to reduce concentration of SARS-CoV-2 viruses in saliva and upper respiratory mucosa and reduce transmission. Clinical trials are in preparation.