or severity. An earlier review stated that vitaminC did not prevent colds, did reduce duration, did not reduce severity. The authors of the Cochrane review concluded that: Vitamin C distributes readily in high concentrations into immune cells, has antimicrobial and natural killer cell activities, promotes lymphocyte proliferation, and is consumed quickly during infections, effects suggesting a prominent role in immune system regulation. The European Food Safety Authority found a cause and effect relationship exists between the dietary intake of vitamin C and functioning of a normal immune system in adults and in children under three years of age. Several studies found Vitamin C to have specific antiviral effects in which it inactivates the RNA or DNA of viruses or in the assembly of the virus. COVID-19 According to ClinicalTrials.gov, as of early 2021 there were 50 completed or ongoing COVID-19 clinical trials including vitamin C as a treatment. A meta-analysis of six published trials was published in October 2021. Treatments were either oral or intravenous. Dose ranged from 50 mg/kg/day to 24 g/day. Reported outcomes were mortality, hospitalization duration, intensive care duration and need for ventilation. From the Conclusion: "The present meta-analysis showed that administration of vitamin C did not have any effect on major health outcomes in COVID infected patients, in comparison to either placebo/standard therapy. Sub-group analysis also revealed that irrespective of its dosage, route of administration and disease severity, it didn't have discernible benefit in such patients. Hence, larger prospective randomized trials are needed in order to evaluate the effect of isolated vitamin C administration, separately for both vitamin C replete and deplete individuals." During March through July 2020, vitamin C was the subject of more US FDA warning letters than any other ingredient for prevention and/or treatment of COVID-19. As of April 2021, the National Institutes of Health (NIH) COVID-19 Treatment Guidelines stated that "there are insufficient data to recommend either for or against the use of vitaminC for the prevention or treatment of COVID-19." Cancer There is no evidence that vitamin C supplementation reduces the risk of lung cancer in healthy people or those at high risk due to smoking or asbestos exposure. A second meta-analysis found no effect on the risk of prostate cancer. Two meta-analyses evaluated the effect of vitamin C supplementation on the risk of colorectal cancer. One found a weak association between vitamin C consumption and reduced risk, and the other