1. Bilezikian JP, Binkley N, De Luca HF, et al. Consensus and Controversial Aspects of Vitamin D and COVID-19. J Clin Endocrinol Metab, 2023; 108(5): 1034-1042. doi: 10.1210/clinem/dgac719.
  2. Pal R, Banerjee M, Bhadada SK, et al. Vitamin D supplementation and clinical outcomes in COVID-19: a systematic review and meta-analysis. J Endocrinol Invest, 2022; 45: 53-68, doi: 10.1007/s40618-021-01614-4.
  3. Ling SF, Broad E, Murphy R, et al. High-Dose Cholecalciferol Booster Therapy is Associated with a Reduced Risk of Mortality in Patients with COVID-19: A Cross-Sectional Multi-Centre Observational Study. Nutrients, 2020; 12: 3799.
  4. Xu Y, Baylink DJ, Chen CS, et al. The importance of vitamin d metabolism as a potential prophylactic, immunoregulatory and neuroprotective treatment for COVID-19. J Transl Med, 2020; 18: 322, doi: 10.1186/s12967-020-02488-5.
  5. Radujkovic A, Hippchen T, Tiwari-Heckler S, et al. Vitamin D Deficiency and Outcome of COVID-19 Patients. Nutrients, 2020; 12: 2757, doi:
  6. Demir M, Demir F, Aygun H. Vitamin D deficiency is associated with COVID-19 positivity and severity of the disease. J Med Virol, 2021; 93: 2992-2999, doi: 10.1002/jmv.26832.
  7. Sulli A, Gotelli E, Casabella A, P et al. Vitamin D and Lung Outcomes in Elderly COVID-19 Patients. Nutrients, 2021; 13: 717, doi:
  8. Kaufman HW, Niles JK, Kroll MH, et al. SARS-CoV-2 positivity rates associated with circulating 25-hydroxyvitamin D levels. PloS one, 2020; 15: e0239252, doi:
  9. Demir AD, Durmaz ZH. A Comparison of Vitamin D Deficiency With Neutrophil Lymphocyte Ratio and CRP Levels in Covid-19 Patients. Med Sci Discov, 2021; 8: 306-309, doi:
  10. Alcala-Diaz JF, Limia-Perez L, Gomez-Huelgas R, et al. Calcifediol Treatment and Hospital Mortality Due to COVID-19: A Cohort Study. Nutrients, 2021; 13: 1760, doi:
  11. Oristrell J, Oliva JC, Casado E, et al. Vitamin D supplementation and COVID-19 risk: a population-based, cohort study. J Endocrinol. Invest, 2022; 45: 167-179, doi:
  12. Murai IH, Fernandes AL, et al. Effect of a Single High Dose of Vitamin D3 on Hospital Length of Stay in Patients With Moderate to Severe COVID-19: A Randomized Clinical Trial. JAMA, 2021; 325: 1053-1060, doi:
  13. Da Rocha AP, Atallah AN, Aldrighi JM, et al. Insufficient evidence for vitamin D use in COVID-19: A rapid systematic review. Int J Clin Pract, 2021; 75: e14649, doi:
  14. Sadeghi-Haddad-Zavareh M, Bayani M, Shokri M, et al. C-Reactive Protein as a Prognostic Indicator in COVID-19 Patients. Interdiscip Perspect Infect Dis, 2021; 5557582, doi:
  15. Tao RX, Zhou QF, Xu ZW, et al. Inverse Correlation between Vitamin D and C-Reactive Protein in Newborns. Nutrients, 2015; 7: 9218-9228, doi:
  16. Kruit A, Zanen P. The Association between Vitamin D and C-Reactive Protein Levels in Patients with Inflammatory and Non-Inflammatory Diseases. Clin Biochem, 2016; 49: 534-537, doi:
  17. Aspell N, Laird E, Healy M, et al. The Prevalence and Determinants of Vitamin D Status in Community-Dwelling Older Adults: Results from the English Longitudinal Study of Ageing (ELSA). Nutrients, 2019; 11: 1253, doi:
  18. Zughaier SM, Alvarez JA, Sloan JH, et al. The Role of Vitamin D in Regulating the Iron-Hepcidin-Ferroportin Axis in Monocytes. J Clin Transl Endocrinol, 2014; 1: e19-e25, doi:
  19. Teama MAEM, Abdelhakam DA, Elmohamadi MA, Badr FM. Vitamin D Deficiency as a Predictor of Severity in Patients with COVID-19 Infection. Sci Prog, 2021; 104: 368504211036854, doi:
  20. Cannata-Andía JB, Díaz-Sottolano A, Fernández P, et al. A Single-Oral Bolus of 100,000 IU of Cholecalciferol at Hospital Admission Did Not Improve Outcomes in the COVID-19 Disease: The COVID-VIT-D—a Randomised Multicentre International Clinical Trial. BMC Med, 2022; 20(1), doi:
  21. Annweiler C, Beaudenon M, Gautier J, et al. High-Dose versus Standard-Dose Vitamin D Supplementation in Older Adults with COVID-19 (COVIT-TRIAL): A Multicenter, Open-Label, Randomized Controlled Superiority Trial. PLOS Med, 2022; 19(5): e1003999, doi:
  22. Sabico S, Enani MA, Sheshah E, et al. Effects of a 2-Week 5000 IU versus 1000 IU Vitamin D3 Supplementation on Recovery of Symptoms in Patients with Mild to Moderate Covid-19: A Randomized Clinical Trial. Nutrients, 2021; 13(7): 2170, doi:
  23. Sánchez-Zuno GA, González-Estevez G, Matuz-Flores MG, et al. Vitamin D Levels in COVID-19 Outpatients from Western Mexico: Clinical Correlation and Effect of Its Supplementation. J Clin Med, 2021; 10(11), doi:
  24. Gómez-Pastora J, Weigand M, Kim J, et al. Hyperferritinemia in Critically Ill COVID-19 Patients – Is Ferritin the Product of Inflammation or a Pathogenic Mediator? Clin Chim Acta; Int J Clin Chem Lab Med, 2020; 509: 249-251, doi:
  25. Lv Y, Chen L, Liang X, et al. Association between Iron Status and the Risk of Adverse Outcomes in COVID-19. Clin Nutr, 2020; 40: 3462-3469, doi:
  26. Kappert K, Jahić A, Tauber R. Assessment of Serum Ferritin as a Biomarker in COVID-19: Bystander or Participant? Insights by Comparison with Other Infectious and Non-Infectious Diseases. Biomarkers, 2020; 1-36, doi:
  27. Lin Z, Long F, Yang Y, et al. Serum Ferritin as an Independent Risk Factor for Severity in COVID-19 Patients. J Infect, 2020; 81: 647-679, doi:
  28. Dahan S, Segal G, Katz I, et al. Ferritin as a Marker of Severity in COVID-19 Patients: A Fatal Correlation. Isr Med Assoc J, 2020; 22(8): 494-500.
  29. Ahmed S, Ansar Ahmed Z, Siddiqui I, et al. Evaluation of Serum Ferritin for Prediction of Severity and Mortality in COVID-19- a Cross Sectional Study. Ann Med Surg, 2021; 63: 102163, doi:
  30. Feld J, Tremblay D, Thibaud S, et al. Ferritin Levels in Patients with COVID‐19: A Poor Predictor of Mortality and Hemophagocytic Lymphohistiocytosis. Clin Lab Haematol, 2020; 42(6): 773-779, doi:
  31. Tural Onur S, Altın S, Sokucu SN, et al. Could Ferritin Level Be an Indicator of COVID‐19 Disease Mortality? J Med Virol, 2020; 93(3): 1672-1677, doi:
  32. Taneri PE, Gómez-Ochoa SA, Llanaj E, et al. Anemia and Iron Metabolism in COVID-19: A Systematic Review and Meta-Analysis. Eur J Epidemiol, 2020; 35(8): 763-773, doi:
  33. Bolondi G, Russo E, et al. Iron Metabolism and Lymphocyte Characterisation during Covid-19 Infection in ICU Patients: An Observational Cohort Study. World J Emerg Surg, 2020; 15(1): 41, doi:
  34. Deng F, Zhang L, Lyu L, et al. Increased Levels of Ferritin on Admission Predicts Intensive Care Unit Mortality in Patients with COVID-19. Medicina Clinica (English Ed.), 2021; 156(7): 324-331, doi:
  35. Banchini F, Cattaneo GM, Capelli P. Serum Ferritin Levels in Inflammation: A Retrospective Comparative Analysis between COVID-19 and Emergency Surgical Non-COVID-19 Patients. World J Emerg Surg, 2021; 16(1): doi:
  36. Colafrancesco S, Alessandri C, Conti F, Priori R. COVID-19 Gone Bad: A New Character in the Spectrum of the Hyperferritinemic Syndrome? Autoimmun Rev, 2020; 19(7): 102573, doi:
  37. Ruscitti P, Berardicurti O, Di Benedetto P, et al. Severe COVID-19, Another Piece in the Puzzle of the Hyperferritinemic Syndrome. An Immunomodulatory Perspective to Alleviate the Storm. Front. Immunol, 2020; 11: 1130, doi:
  38. Perricone C, Bartoloni E, Bursi R, et al. COVID-19 as Part of the Hyperferritinemic Syndromes: The Role of Iron Depletion Therapy. Immunol Res, 2020; 1-12, doi:
  39. Zhou F, Yu T, Du R, et al. Clinical Course and Risk Factors for Mortality of Adult Inpatients with COVID-19 in Wuhan, China: A Retrospective Cohort Study. The Lancet, 2020; 395(10229): 1054-1062, doi:
  40. Ruscitti P, Giacomelli R. Ferritin and Severe COVID-19, from Clinical Observations to Pathogenic Implications and Therapeutic Perspectives. The Israel Medical Association journal: IMAJ, 2020; 22(8): 516-518.
  41. Wu C, Chen X, Cai Y, et al. Risk Factors Associated with Acute Respiratory Distress Syndrome and Death in Patients with Coronavirus Disease 2019 Pneumonia in Wuhan, China. JAMA, 2020; 180(7), doi:
  42. Kell DB, Pretorius E. Serum Ferritin Is an Important Inflammatory Disease Marker, as It Is Mainly a Leakage Product from Damaged Cells. Metallomics: integrated biometal science, 2014; 6(4): 748-773, doi:
  43. Fernandes AL, Murai IH, Reis BZ, et al. Effect of a Single High Dose of Vitamin D3 on Cytokines, Chemokines, and Growth Factor in Patients with Moderate to Severe COVID-19. Am J Clin Nutr, 2022; 115(3): 790-798, doi:
  44. Rastogi A, Bhansali A, Khare N, et al. Short term, high-dose vitamin D supplementation for COVID-19 disease: a randomised, placebo-controlled, study (SHADE study). Postgraduate Med J, 2022; 98(1156): 87-90.
  45. Calton EK, Keane KN, et al. The Impact of Vitamin D Levels on Inflammatory Status: A Systematic Review of Immune Cell Studies. PloS one, 2015; 10(11): e0141770.