“OMNS (Sept. 20, 2022) Just 1,000 milligrams per day of niacinamide, which costs about 5 cents, has been shown to clearly reduce mortality in patients with COVID-19-related acute kidney injury (AKI) by 25% [1] Investigators observed that "niacinamide administered for the prevention of COVID-19-related AKI progression was safe and associated with reduced estimated risk of death or the need for renal replacement therapy compared with historical controls. The association was strongest in severe AKI.”

http://www.orthomolecular.org/resources/omns/v18n25.shtml