evidence: Vitamins C and D and COVID-19 Susceptibility, Severity and Progression: An Evidence Based Systematic Review - PMID: 35888660 - PMCID: PMC9318801 - DOI: 10.3390/medicina58070941 Vitamins C and D and COVID-19 Susceptibility, Severity and Progression: An Evidence Based Systematic Review [...] Multi-Level Immune Support by Vitamins C and D during the SARS-CoV-2 Pandemic.Nutrients. 2022 Feb 6;14(3):689. doi: 10.3390/nu14030689. Nutrients. 2022. PMID: 35277048 Free PMC article. Review.