Abstract
Introduction: With millions of cases and deaths worldwide, coronavirus disease 2019 (COVID-19) is the greatest public health crisis in global history, with severe atypical pneumonia as its most common cause of death. Vitamin C is an essential nutrient that cannot be synthesized by the human body, but it is effective against a variety of upper respiratory infections, preventing hyperinflammatory responses and speeding up healing of infected areas. Vitamin C deficiency frequently coexists with COVID-19. Objective This review provides an up-to-date overview of recent epidemiological and intervention findings on vitamin C supplementation for reducing severe COVID-19 disease and mortality. Materials and methods: The databases of PubMed, ScienceDirect, Scopus, Cochrane, and Google Scholar were searched for pertinent literature from the beginning of the COVID-19 pandemic until January 12, 2022.Results and discussion: Known risk factors for extreme COVID-19 include advanced age, preexisting conditions, and vitamin C deficiency. Vitamin deficiencies are modifiable risk factors, and supplementation has been shown to minimize the risk of influenza in observational studies and clinical trials. Mounting evidence strongly supports widespread vitamin C supplementation, especially among high-risk populations, as well as high-dose supplementation for the infected ones. Conclusions: The risk-benefit ratio of vitamin C supplementation Calls for decisive intervention, ahead of the results of ongoing large-scale randomized trials.