{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T10:19:53Z","timestamp":1783937993642,"version":"3.55.0"},"reference-count":124,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,2,14]],"date-time":"2026-02-14T00:00:00Z","timestamp":1771027200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100018987","name":"Ministry of Research, Innovation and Digitization","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100018987","id-type":"DOI","asserted-by":"crossref"}]},{"name":"project \u201cArtificial intelligence-powered personalized health and genomics libraries for the analysis of long-term effects in COVID-19 patients (AI-PHGL-COVID)\u201d","award":["760073\/23.05.2023"],"award-info":[{"award-number":["760073\/23.05.2023"]}]},{"name":"project \u201cArtificial intelligence-powered personalized health and genomics libraries for the analysis of long-term effects in COVID-19 patients (AI-PHGL-COVID)\u201d","award":["285\/30.11.2022"],"award-info":[{"award-number":["285\/30.11.2022"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Vitamin D is a secosteroid hormone traditionally recognized for its role in bone and mineral metabolism, but it is increasingly understood to also function as an important immunomodulator influencing susceptibility to and outcomes of infectious diseases. This narrative review summarizes current evidence on the immunological, clinical, and preventive effects of vitamin D in the context of novel coronavirus disease (COVID-19), post-acute sequelae of SARS-CoV-2 infection (long COVID), and influenza. Mechanistically, vitamin D enhances innate immune defenses through the induction of antimicrobial peptides, including cathelicidin and defensins, and modulates adaptive immunity by suppressing maladaptive Th1\/Th17 responses while promoting regulatory T-cell activity. Observational studies have frequently associated vitamin D deficiency with more severe COVID-19 outcomes; however, these associations may be influenced by confounding factors and reverse causality. Some meta-analyses suggest that vitamin D supplementation reduced rates of intensive care unit admission and ventilatory support, particularly among older adults and individuals with low baseline serum 25-hydroxyvitamin D concentrations. Emerging evidence also indicates that inadequate vitamin D status may be associated with an increased risk and symptom burden of long COVID, although causality has not been established. In the case of influenza, a limited number of randomized controlled trials (RCTs) and meta-analyses report a modest but statistically significant reduction in infection risk, especially with daily or weekly vitamin D supplementation in populations with low baseline vitamin D levels. Clinical guidelines consistently recommend maintaining adequate vitamin D status for general health but do not endorse high-dose vitamin D as a treatment for COVID-19 due to inconsistent trial findings. Overall, vitamin D should not be considered a standalone therapeutic agent; rather, maintaining sufficient vitamin D levels represents a low-risk, potentially beneficial strategy to support immune resilience against respiratory viral infections.<\/jats:p>","DOI":"10.3390\/nu18040634","type":"journal-article","created":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T14:09:54Z","timestamp":1771250994000},"page":"634","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Vitamin D in Infectious Diseases: A Narrative Review Focusing on COVID-19, Long COVID, and Influenza"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2274-6439","authenticated-orcid":false,"given":"Olga Adriana","family":"Caliman-Sturdza","sequence":"first","affiliation":[{"name":"Faculty of Medicine and Biological Sciences, Stefan cel Mare University of Suceava, 720229 Suceava, Romania"},{"name":"Suceava Emergency Clinical County Hospital, 720224 Suceava, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roxana Elena","family":"Gheorghita","sequence":"additional","affiliation":[{"name":"Faculty of Medicine and Biological Sciences, Stefan cel Mare University of Suceava, 720229 Suceava, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8625-4033","authenticated-orcid":false,"given":"Iuliana","family":"Soldanescu","sequence":"additional","affiliation":[{"name":"Integrated Center for Research, Development, and Innovation for Advanced Materials, Nanotechnologies, Manufacturing and Control Distributed Systems (MANSiD), Stefan cel Mare University of Suceava, 720229 Suceava, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2093-8659","authenticated-orcid":false,"given":"Mihai","family":"Dimian","sequence":"additional","affiliation":[{"name":"Integrated Center for Research, Development, and Innovation for Advanced Materials, Nanotechnologies, Manufacturing and Control Distributed Systems (MANSiD), Stefan cel Mare University of Suceava, 720229 Suceava, Romania"},{"name":"Department of Computers, Electronics and Automation, Stefan cel Mare University of Suceava, 720229 Suceava, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Serghei","family":"Mangul","sequence":"additional","affiliation":[{"name":"Faculty of Medicine and Biological Sciences, Stefan cel Mare University of Suceava, 720229 Suceava, Romania"},{"name":"Department of Clinical Pharmacy, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California (USC), Los Angeles, CA 90033, USA"},{"name":"Department of Quantitative and Computational Biology, USC Dornsife College of Letters, Arts and Sciences, University of Southern California (USC), Los Angeles, CA 90089, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"881","DOI":"10.2310\/JIM.0b013e31821b8755","article-title":"Vitamin D and the immune system","volume":"59","author":"Aranow","year":"2011","journal-title":"J. Investig. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1038\/s41584-023-00944-2","article-title":"Involvement of the secosteroid vitamin D in autoimmune rheumatic diseases and COVID-19","volume":"19","author":"Cutolo","year":"2023","journal-title":"Nat. Rev. Rheumatol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1757","DOI":"10.1093\/nutrit\/nuae225","article-title":"Association Between Vitamin D and COVID-19\u2013Related Outcomes: An Umbrella Review of Meta-Analyses","volume":"83","author":"Yang","year":"2025","journal-title":"Nutr. Rev."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"e102","DOI":"10.1016\/S1473-3099(21)00703-9","article-title":"WHO Clinical Case Definition Working Group on Post-COVID-19 Condition. A clinical case definition of post-COVID-19 condition by a Delphi consensus","volume":"22","author":"Soriano","year":"2022","journal-title":"Lancet Infect. Dis."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Tomaszewska, A., Rustecka, A., Lipi\u0144ska-Opa\u0142ka, A., Piprek, R.P., Kloc, M., Kalicki, B., and Kubiak, J.Z. (2022). The role of vitamin D in COVID-19 and the impact of pandemic restrictions on vitamin D blood content. Front. Pharmacol., 13.","DOI":"10.3389\/fphar.2022.836738"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Aribi, M., Mennechet, F.J.D., and Touil-Boukoffa, C. (2023). Editorial: The role of vitamin D as an immunomodulator. Front. Immunol., 14.","DOI":"10.3389\/fimmu.2023.1186635"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"109105","DOI":"10.1016\/j.jnutbio.2022.109105","article-title":"Vitamin D boosts immune response of macrophages through a regulatory network of microRNAs and mRNAs","volume":"109","author":"Fernandez","year":"2022","journal-title":"J. Nutr. Biochem."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Fiske, C.T., Blackman, A., Maruri, F., Rebeiro, P., Huaman, M., Kator, J., Algood, H., and Sterling, T. (2019). Increased vitamin D receptor expression from macrophages after stimulation with Mycobacterium tuberculosis. BMC Infect. Dis., 19.","DOI":"10.1186\/s12879-019-3958-7"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"4289","DOI":"10.4049\/jimmunol.0803736","article-title":"Vitamin D-directed rheostatic regulation of monocyte antibacterial responses","volume":"182","author":"Adams","year":"2009","journal-title":"J. Immunol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"e12","DOI":"10.4110\/in.2020.20.e12","article-title":"Vitamin D-Cathelicidin Axis: At the Crossroads between Protective Immunity and Pathological Inflammation during Infection","volume":"20","author":"Chung","year":"2020","journal-title":"Immune Netw."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Bukvi\u0107 Mokos, Z., Tomi\u0107 Krsnik, L., Harak, K., Tomic, D., Petrovic, D., and Vukojevic, M. (2025). Vitamin D in the Prevention and Treatment of Inflammatory Skin Diseases. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms26115005"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"13514","DOI":"10.3390\/cimb46120807","article-title":"The Anti-Inflammatory Roles of Vitamin D for Improving Human Health","volume":"46","author":"Fenercioglu","year":"2024","journal-title":"Curr. Issues Mol. Biol."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Petrelli, F., Oldani, S., Borgonovo, K., Cabiddu, M., Dognini, G., Ghilardi, M., Parati, M.C., Petro\u2019, D., Dottorini, L., and Rea, C. (2023). Vitamin D3 and COVID-19 Outcomes: An Umbrella Review of Systematic Reviews and Meta-Analyses. Antioxidants, 12.","DOI":"10.3390\/antiox12020247"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Argano, C., Torres, A., Orlando, V., Cangialosi, V., Maggio, D., Pollicino, C., and Corrao, S. (2025). Molecular Insight into the Role of Vitamin D in Immune-Mediated Inflammatory Diseases. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms26104798"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1151","DOI":"10.2217\/fmb.09.87","article-title":"The vitamin D-antimicrobial peptide pathway and its role in protection against infection","volume":"4","author":"Gombart","year":"2009","journal-title":"Future Microbiol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Ghaseminejad-Raeini, A., Ghaderi, A., Sharafi, A., Nematollahi-Sani, B., Moossavi, M., Derakhshani, A., and Sarab, G.A. (2023). Immunomodulatory actions of vitamin D in various immune-related disorders: A comprehensive review. Front. Immunol., 14.","DOI":"10.3389\/fimmu.2023.950465"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Shang, S., Chen, D., Wei, Y., Zou, S., Chang, Q., Zhou, H., and Yu, A. (2025). The Role of Vitamin D and Vitamin D Receptor in Sepsis. Curr. Issues Mol. Biol., 47.","DOI":"10.3390\/cimb47070500"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Kim, E.W., Teles, R.M.B., Haile, S., Liu, P.T., and Modlin, R.L. (2018). Vitamin D status contributes to antimicrobial activity of macro-phages. PLoS Negl. Trop. Dis., 12.","DOI":"10.1371\/journal.pntd.0006608"},{"key":"ref_19","first-page":"e10405","article-title":"Vitamin D and Immune Regulation: Antibacterial, Antiviral, Anti-Inflammatory","volume":"5","author":"Ismailova","year":"2021","journal-title":"J. Bone Miner. Res. Plus"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"E246","DOI":"10.1152\/ajpendo.00174.2021","article-title":"Vitamin D and lumisterol novel metabolites can inhibit SARS-CoV-2 replication machinery enzymes","volume":"321","author":"Qayyum","year":"2021","journal-title":"Am. J. Physiol. Endocrinol. Metab."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Wimalawansa, S.J. (2024). Unveiling the Interplay\u2014Vitamin D and ACE-2 Molecular Interactions in Mitigating Complications and Deaths from SARS-CoV-2. Biology, 13.","DOI":"10.3390\/biology13100831"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Albergamo, A., Apprato, G., and Silvagno, F. (2022). The Role of Vitamin D in Supporting Health in the COVID-19 Era. Int. J. Mol. Sci., 23.","DOI":"10.3390\/ijms23073621"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"232","DOI":"10.18683\/germs.2024.1435","article-title":"Vitamin D and COVID-19: Comparative Analysis with Other Respiratory Infections and impact of Comorbidities","volume":"14","author":"Constantin","year":"2024","journal-title":"Germs"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.nfs.2020.06.001","article-title":"Vitamin D deficiency and co-morbidities in COVID-19 patients\u2014A fatal relationship?","volume":"20","author":"Biesalski","year":"2020","journal-title":"Nfs J."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1093\/nutrit\/nuaf086","article-title":"Vitamin D and Influenza: Immunological Insights and Therapeutic Potential for Respiratory Health","volume":"84","author":"Pandey","year":"2026","journal-title":"Nutr. Rev."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Galindo-M\u00e9ndez, M., Galindo-Ruiz, M., Concheso-Venegas, M.F., Mendoza-Molina, S.U., Orozco-Cruz, D., and Weintraub-Benzion, E. (2025). The Impact of Vitamin D in the Prevention of Influenza, COVID-19, and Dengue: A Review. Biomedicines, 13.","DOI":"10.3390\/biomedicines13040927"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Toledano, J.M., Moreno-Fernandez, J., Puche-Juarez, M., Ochoa, J.J., and Diaz-Castro, J. (2022). Implications of Vitamins in COVID-19 Prevention and Treatment through Immunomodulatory and Anti-Oxidative Mechanisms. Antioxidants, 11.","DOI":"10.3390\/antiox11010005"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Bleakley, A.S., Licciardi, P.V., and Binks, M.J. (2021). Vitamin D Modulation of the Innate Immune Response to Paediatric Respiratory Pathogens Associated with Acute Lower Respiratory Infections. Nutrients, 13.","DOI":"10.3390\/nu13010276"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Grant, W.B., Lahore, H., McDonnell, S.L., Baggerly, C.A., French, C.B., Aliano, J.L., and Bhattoa, H.P. (2020). Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients, 12.","DOI":"10.20944\/preprints202003.0235.v2"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1109","DOI":"10.3889\/oamjms.2021.6992","article-title":"The Role of Vitamin D in Respiratory Viral Infections and Other Infectious Diseases","volume":"9","author":"Dyussenova","year":"2021","journal-title":"Open Access Maced. J. Med. Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"e003176","DOI":"10.1136\/bmjgh-2020-003176","article-title":"Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: A systematic review and meta-analysis","volume":"6","author":"Abioye","year":"2021","journal-title":"BMJ Glob. Health"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1129","DOI":"10.1017\/S0950268806007175","article-title":"Epidemic influenza and vitamin D","volume":"134","author":"Cannell","year":"2006","journal-title":"Epidemiol. Infect."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1255","DOI":"10.3945\/ajcn.2009.29094","article-title":"Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren","volume":"91","author":"Urashima","year":"2010","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2365","DOI":"10.1039\/C4FO00371C","article-title":"Effects of vitamin D supplements on influenza A illness during the 2009 H1N1 pandemic: A randomized controlled trial","volume":"5","author":"Urashima","year":"2014","journal-title":"Food Funct."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"40","DOI":"10.2174\/1573395513666171031162100","article-title":"Immunomodulatory Effects of Vitamin D in Influenza Infection","volume":"14","author":"Rezaei","year":"2018","journal-title":"Curr. Immunol. Rev."},{"key":"ref_36","first-page":"246737","article-title":"Role of Fat-Soluble Vitamins A and D in the Pathogenesis of Influenza: A New Perspective","volume":"2013","author":"Mawson","year":"2013","journal-title":"Int. Sch. Res. Not."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Zhu, Z., Zhu, X., Gu, L., Zhan, Y., Chen, L., and Li, X. (2022). Association Between Vitamin D and Influenza: Meta-Analysis and Systematic Review of Randomized Controlled Trials. Front. Nutr., 8.","DOI":"10.3389\/fnut.2021.799709"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"i6583","DOI":"10.1136\/bmj.i6583","article-title":"Vitamin D supplementation to prevent acute respiratory tract infections: Systematic review and meta-analysis of individual participant data","volume":"356","author":"Martineau","year":"2017","journal-title":"BMJ"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1016\/S2213-8587(21)00051-6","article-title":"Vitamin D supplementation to prevent acute respiratory infections: A systematic review and meta-analysis of aggregate data from randomised controlled trials","volume":"9","author":"Jolliffe","year":"2021","journal-title":"Lancet Diabetes Endocrinol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"625","DOI":"10.1210\/endrev\/bnae009","article-title":"Consensus Statement on Vitamin D Status Assessment and Supplementation: Whys, Whens, and Hows","volume":"45","author":"Giustina","year":"2024","journal-title":"Endocr. Rev."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Gruber-Bzura, B.M. (2018). Vitamin D and Influenza\u2014Prevention or Therapy?. Int. J. Mol. Sci., 19.","DOI":"10.3390\/ijms19082419"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"e17252","DOI":"10.1097\/MD.0000000000017252","article-title":"The association between vitamin D deficiency and community-acquired pneumonia: A meta-analysis of observational studies","volume":"98","author":"Zhou","year":"2019","journal-title":"Medicine"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1111\/1756-185X.14477","article-title":"Vitamin D\u2014A prominent immunomodulator to prevent COVID-19 infection","volume":"26","author":"Ashique","year":"2023","journal-title":"Int. J. Rheum. Dis."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Rizzi, M., and Sainaghi, P.P. (2025). Vitamin D: A Nutraceutical Supplement at the Crossroad Between Respiratory Infections and COVID-19. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms26062550"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Sarhan, N., Abou Warda, A.E., Sarhan, R.M., Boshra, M.S., Mostafa-Hedeab, G., ALruwaili, B.F., Ibrahim, H.S.G., Schaalan, M.F., and Fathy, S. (2022). Evidence for the Efficacy of a High Dose of Vitamin D on the Hyperinflammation State in Moderate-to-Severe COVID-19 Patients: A Randomized Clinical Trial. Medicina, 58.","DOI":"10.3390\/medicina58101358"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"953","DOI":"10.1136\/thoraxjnl-2015-206996","article-title":"Double-blind randomised controlled trial of vitamin D3 supplementation for the prevention of acute respiratory infection in older adults and their carers (ViDiFlu)","volume":"70","author":"Martineau","year":"2015","journal-title":"Thorax"},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Marusca, L.M., Reddy, G., Blaj, M., Prathipati, R., Rosca, O., Bratosin, F., Bogdan, I., Horhat, R.M., Tapos, G.-F., and Marti, D.-T. (2023). The Effects of Vitamin D Supplementation on Respiratory Infections in Children under 6 Years Old: A Systematic Review. Diseases, 11.","DOI":"10.3390\/diseases11030104"},{"key":"ref_48","unstructured":"National Institute for Health and Care Excellence (NICE) (2025, December 10). COVID-19 Rapid Guideline: Vitamin D (NG187), Available online: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK566063\/."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Jia, H., Sheng, F., Yan, Y., Liu, X., and Zeng, B. (2024). Vitamin D supplementation for prevention of acute respiratory infections in older adults: A systematic review and meta-analysis. PLoS ONE, 19.","DOI":"10.1371\/journal.pone.0303495"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"749","DOI":"10.1097\/INF.0000000000001890","article-title":"Preventive Effects of Vitamin D on Seasonal Influenza A in Infants: A Multicenter, Randomized, Open, Controlled Clinical Trial","volume":"37","author":"Zhou","year":"2018","journal-title":"Pediatr. Infect. Dis. J."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1111\/irv.12615","article-title":"Effect of Vitamin D supplementation to reduce respiratory infections in children and adolescents in Vietnam: A randomized controlled trial","volume":"13","author":"Loeb","year":"2019","journal-title":"Influenza Other Respir. Viruses"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1001\/jama.2017.8708","article-title":"Effect of High-Dose vs. Standard-Dose Wintertime Vitamin D Supplementation on Viral Upper Respiratory Tract Infections in Young Healthy Children","volume":"318","author":"Aglipay","year":"2017","journal-title":"JAMA"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1088","DOI":"10.1093\/ibd\/izy346","article-title":"Randomized Trial of Vitamin D Supplementation to Prevent Seasonal Influenza and Upper Respiratory Infection in Patients With Inflammatory Bowel Disease","volume":"25","author":"Arihiro","year":"2019","journal-title":"Inflamm. Bowel Dis."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Wang, X., Li, J., Liu, H., Hu, X., Lin, Z., and Xiong, N. (2023). SARS-CoV-2 versus Influenza A Virus: Characteristics and Co-Treatments. Microorganisms, 11.","DOI":"10.3390\/microorganisms11030580"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"126","DOI":"10.3109\/00365548.2011.621446","article-title":"Vitamin D supplementation did not prevent influenza-like illness as diagnosed retrospectively by questionnaires in subjects participating in randomized clinical trials","volume":"44","author":"Jorde","year":"2012","journal-title":"Scand. J. Infect. Dis."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"20191","DOI":"10.1038\/s41598-020-77093-z","article-title":"Analysis of Vitamin D level among asymptomatic and critically ill COVID-19 patients and its correlation with inflammatory markers","volume":"10","author":"Jain","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1093\/jn\/nxaa332","article-title":"Vitamin D deficiency is associated with COVID-19 incidence and disease severity in Chinese People [corrected]","volume":"151","author":"Luo","year":"2021","journal-title":"J. Nutr."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"e1343","DOI":"10.1210\/clinem\/dgaa733","article-title":"Vitamin D status in hospitalized patients with SARS-CoV-2 infection","volume":"106","author":"Nan","year":"2021","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1080\/07315724.2020.1856013","article-title":"Vitamin D deficiency as a predictor of poor prognosis in severe COVID-19","volume":"40","author":"Bennouar","year":"2021","journal-title":"J. Am. Coll. Nutr."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"81","DOI":"10.15605\/jafes.038.01.07","article-title":"Association of Vitamin D levels on the Clinical Outcomes of Patients Hospitalized for COVID-19 in a Tertiary Hospital","volume":"38","author":"Tan","year":"2023","journal-title":"J. ASEAN Fed. Endocr. Soc."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"255","DOI":"10.4103\/CIDS.CIDS_5_23","article-title":"A Prospective Observational Study on the Association of Serum 25-hydroxy Vitamin D Levels with Clinical Outcomes among COVID-19 Patients Admitted to a Tertiary Care Facility, South India","volume":"1","author":"Thomas","year":"2023","journal-title":"J. Clin. Infect. Dis. Soc."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"2199","DOI":"10.1093\/jn\/nxab107","article-title":"Low Circulating Vitamin D in Intensive Care Unit-Admitted COVID-19 Patients as a Predictor of Negative Outcomes","volume":"151","author":"Bychinin","year":"2021","journal-title":"J. Nutr."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"84","DOI":"10.4103\/jfmpc.jfmpc_1600_20","article-title":"Severe COVID-19: A distinct entity","volume":"10","author":"Garg","year":"2021","journal-title":"J. Family Med. Prim. Care"},{"key":"ref_64","doi-asserted-by":"crossref","unstructured":"Bushnaq, T., Algethami, F., Qadhi, A., Mustafa, R., Ghafouri, K., Azhar, W., and Malki, A.A. (2022). The Impact of Vitamin D Status on COVID-19 Severity among Hospitalized Patients in the Western Region of Saudi Arabia: A Retrospective Cross-Sectional Study. Int. J. Environ. Res. Public Health, 19.","DOI":"10.3390\/ijerph19031901"},{"key":"ref_65","doi-asserted-by":"crossref","unstructured":"Zhang, Y., Li, J., Yang, M., and Wang, Q. (2023). Effect of vitamin D supplementation on COVID-19 patients: A systematic review and meta-analysis. Front. Nutr., 10.","DOI":"10.3389\/fnut.2023.1131103"},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1111\/cen.14540","article-title":"Association of vitamin D deficiency with COVID-19 infection severity: Systematic review and meta-analysis","volume":"96","author":"Wang","year":"2022","journal-title":"Clin. Endocrinol."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"e091903","DOI":"10.1136\/bmjopen-2024-091903","article-title":"Vitamin D supplementation for managing COVID-19 in patients with vitamin D deficiency: A systematic review and meta-analysis of randomised controlled trials","volume":"15","author":"Zhu","year":"2025","journal-title":"BMJ Open"},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1007\/s12020-023-03331-9","article-title":"Low vitamin D levels predict outcomes of COVID-19 in patients with both severe and non-severe disease at hospitalization","volume":"80","author":"Uygur","year":"2023","journal-title":"Endocrine"},{"key":"ref_69","first-page":"679","article-title":"Association between Vitamin D Status and Risk of Developing Severe COVID-19 Infection: A Meta-Analysis of Observational Studies","volume":"41","author":"Hopefl","year":"2022","journal-title":"J. Am. Nutr. Assoc."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1016\/j.nutos.2025.05.007","article-title":"Exploring the association between vitamin D status and Corona Virus-19 infection in a cohort of adults aged 50 years and older","volume":"62","author":"Wagner","year":"2025","journal-title":"Clin. Nutr. Open Sci."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"561","DOI":"10.1016\/j.dsx.2020.04.050","article-title":"Vitamin D concentrations and COVID-19 infection in UK Biobank","volume":"14","author":"Hastie","year":"2020","journal-title":"Diabetes Metab. Syndr."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"321","DOI":"10.3961\/jpmph.21.640","article-title":"Vitamin D deficiency and comorbidities as risk factors of COVID-19 infection: A systematic review and meta-analysis","volume":"55","author":"Mishra","year":"2022","journal-title":"J. Prev. Med. Public Health"},{"key":"ref_73","doi-asserted-by":"crossref","unstructured":"Caliman-Sturdza, O.A., Gheorghita, R.E., and Soldanescu, I. (2025). Vitamin D and COVID-19: Clinical Evidence and Immunological Insights. Life, 15.","DOI":"10.3390\/life15050733"},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"579","DOI":"10.1007\/s11154-021-09705-6","article-title":"Association of vitamin D status with COVID-19 and its severity: Vitamin D and COVID-19: A narrative review","volume":"23","author":"Bae","year":"2022","journal-title":"Rev. Endocr. Metab. Disord."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"8772","DOI":"10.1038\/s41467-025-64192-6","article-title":"Monitoring changes in vitamin D levels during the COVID-19 pandemic with routinely collected laboratory data","volume":"16","author":"Skapetze","year":"2025","journal-title":"Nat. Commun."},{"key":"ref_76","doi-asserted-by":"crossref","unstructured":"Akbar, M.R., Wibowo, A., Pranata, R., and Setiabudiawan, B. (2021). Low serum 25-hydroxyvitamin D (Vitamin D) level is associated with susceptibility to COVID-19, severity, and mortality: A systematic review and meta-analysis. Front. Nutr., 8.","DOI":"10.3389\/fnut.2021.754539"},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"e2021074","DOI":"10.4178\/epih.e2021074","article-title":"The role of vitamin D deficiency on COVID-19: A systematic review and meta-analysis of observational studies","volume":"43","author":"Kaya","year":"2021","journal-title":"Epidemiol. Health"},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1111\/joim.13149","article-title":"Perspective: Vitamin D deficiency and COVID-19 severity\u2014Plausibly linked by latitude, ethnicity, impacts on cytokines, ACE2 and thrombosis","volume":"289","author":"Rhodes","year":"2021","journal-title":"J. Intern. Med."},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"254","DOI":"10.12688\/f1000research.131730.2","article-title":"The effect of Vitamin D levels on the course of COVID-19 in hospitalized patients\u2014A 1-year prospective cohort study [version 2; peer review: 1 approved, 1 approved with reservations]","volume":"12","author":"Siuka","year":"2024","journal-title":"F1000Research"},{"key":"ref_80","first-page":"e26266","article-title":"Association between vitamin D serum level and COVID-19 outcomes in a tertiary center in Saudi Arabia","volume":"14","author":"Alzahrani","year":"2022","journal-title":"Cureus"},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"23986","DOI":"10.1038\/s41598-025-08621-y","article-title":"Association between 25(OH)D levels and clinical outcomes in patients infected with SARS-CoV-2: A cross-sectional study","volume":"15","author":"Starosz","year":"2025","journal-title":"Sci. Rep."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"105751","DOI":"10.1016\/j.jsbmb.2020.105751","article-title":"Effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for COVID-19: A pilot randomized clinical study","volume":"203","author":"Miranda","year":"2020","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"1053","DOI":"10.1001\/jama.2020.26848","article-title":"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","volume":"325","author":"Murai","year":"2021","journal-title":"JAMA"},{"key":"ref_84","doi-asserted-by":"crossref","unstructured":"Feiner Sol\u00eds, \u00c1., Avedillo Salas, A., Luesma Bartolom\u00e9, M.J., and Santander Ballest\u00edn, S. (2022). The Effects of Vitamin D Supplementation in COVID-19 Patients: A Systematic Review. Int. J. Mol. Sci., 23.","DOI":"10.3390\/ijms232012424"},{"key":"ref_85","doi-asserted-by":"crossref","unstructured":"Huang, L., Song, Z., Lu, C., Wang, S., Guo, C., Lai, X.H., and Zhao, Z. (2025). A narrative review focusing on randomized clinical trials of vitamin D supplementation for COVID-19 disease. Front. Nutr., 11.","DOI":"10.3389\/fnut.2024.1461485"},{"key":"ref_86","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1016\/j.arcmed.2022.04.003","article-title":"Efficacy and Safety of Vitamin D Supplementation to Prevent COVID-19 in Frontline Healthcare Workers. A Randomized Clinical Trial","volume":"53","year":"2022","journal-title":"Arch. Med. Res."},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"e071245","DOI":"10.1136\/bmj-2022-071245","article-title":"Prevention of COVID-19 and other acute respiratory infections with cod liver oil supplementation, a low dose vitamin D supplement: Quadruple blinded, randomised placebo controlled trial","volume":"378","author":"Brunvoll","year":"2022","journal-title":"BMJ"},{"key":"ref_88","doi-asserted-by":"crossref","unstructured":"Sartini, M., Del Puente, F., Carbone, A., Schinca, E., Ottria, G., Dupont, C., Piccinini, C., Oliva, M., and Cristina, M.L. (2024). The Effect of Vitamin D Supplementation Post COVID-19 Infection and Related Outcomes: A Systematic Review and Meta-Analysis. Nutrients, 16.","DOI":"10.3390\/nu16223794"},{"key":"ref_89","doi-asserted-by":"crossref","unstructured":"K\u00fcmmel, L.S., Krumbein, H., Fragkou, P.C., H\u00fcnerbein, B., Reiter, R., Papathanasiou, K., Th\u00f6lken, C., Weiss, S., Renz, H., and Skevaki, C. (2022). Vitamin D supplementation for the treatment of COVID-19: A systematic review and meta-analysis of randomized controlled trials. Front. Immunol., 13.","DOI":"10.3389\/fimmu.2022.1023903"},{"key":"ref_90","doi-asserted-by":"crossref","unstructured":"Yang, Y., Sun, W., Yang, F., Zhang, G., Li, X., Sun, S., and Xing, Y. (2024). Therapeutic effects of vitamin D supplementation on COVID-19 aggravation: A systematic review and meta-analysis of randomized controlled trials. Front. Pharmacol., 15.","DOI":"10.3389\/fphar.2024.1367686"},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1186\/s12937-021-00744-y","article-title":"Low vitamin D levels do not aggravate COVID-19 risk or death, and vitamin D supplementation does not improve outcomes in hospitalized patients with COVID-19: A meta-analysis and GRADE assessment of cohort studies and RCTs","volume":"20","author":"Chen","year":"2021","journal-title":"Nutr. J."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"1523","DOI":"10.3389\/fimmu.2020.01523","article-title":"Vitamin D Supplementation: A Potential Approach for Coronavirus\/COVID-19 Therapeutics?","volume":"11","author":"Arboleda","year":"2020","journal-title":"Front. Immunol."},{"key":"ref_93","doi-asserted-by":"crossref","first-page":"1133","DOI":"10.1210\/jc.2016-3919","article-title":"Effects of Cholecalciferol vs. Calcifediol on Total and Free 25-Hydroxyvitamin D and Parathyroid Hormone","volume":"102","author":"Shieh","year":"2017","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_94","doi-asserted-by":"crossref","unstructured":"Ortiz-Prado, E., Vasconez-Gonzalez, J., Izquierdo-Condoy, J.S., Su\u00e1rez-Sangucho, I.A., Prieto-Mar\u00edn, J.G., Villarreal-Burbano, K.B., Barriga-Collantes, M.A., Altamirano-Castillo, J.A., Borja-Mendoza, D.A., and Pazmi\u00f1o-Almeida, J.C. (2025). Cholecalciferol (vitamin D3): Efficacy, safety, and implications in public health. Front. Nutr., 9.","DOI":"10.3389\/fnut.2025.1579957"},{"key":"ref_95","doi-asserted-by":"crossref","first-page":"10804","DOI":"10.1038\/s41598-021-90019-7","article-title":"Power determination in vitamin D randomised control trials and characterising factors affecting it through a novel simulation-based tool","volume":"11","author":"Wyse","year":"2021","journal-title":"Sci. Rep."},{"key":"ref_96","doi-asserted-by":"crossref","first-page":"1624","DOI":"10.1038\/s41430-022-01159-6","article-title":"The role of baseline serum 25(OH)D concentration for a potential personalized vitamin D supplementation","volume":"76","author":"Ferrario","year":"2022","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_97","doi-asserted-by":"crossref","first-page":"202","DOI":"10.1177\/15598276221140864","article-title":"Potential Benefit of Vitamin D Supplementation in COVID-19","volume":"17","author":"Stafford","year":"2022","journal-title":"Am. J. Lifestyle Med."},{"key":"ref_98","doi-asserted-by":"crossref","unstructured":"Jafari-Vayghan, H., Rahimlou, M., Almasi-Hashiani, A., Aframehr, E., and Saleh-Ghadimi, S. (2025). Effect of the vitamin D supplementation on clinical outcomes and inflammatory status in COVID-19 patients: An umbrella review. BMC Nutr., 11.","DOI":"10.1186\/s40795-025-01060-y"},{"key":"ref_99","doi-asserted-by":"crossref","first-page":"e1106","DOI":"10.1210\/clinem\/dgad207","article-title":"Low Vitamin D Levels Are Associated With Long COVID Syndrome in COVID-19 Survivors","volume":"108","author":"Frara","year":"2023","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_100","doi-asserted-by":"crossref","unstructured":"Matsuda, Y., Sakurada, Y., Nakano, Y., Otsuka, Y., Tokumasu, K., Honda, H., Soejima, Y., Yokota, Y., Takase, R., and Omura, D. (2025). Clinical Characteristics of Vitamin D Deficiency Detected in Long COVID Patients During the Omicron Phase. Nutrients, 17.","DOI":"10.3390\/nu17101692"},{"key":"ref_101","doi-asserted-by":"crossref","unstructured":"Matangkha, K., Punyahotara, V., Rintra, J., and Sittiprapaporn, P. (2025). Association Between Vitamin D Levels and Long COVID Signs and Symptoms. Med. Sci., 13.","DOI":"10.3390\/medsci13030199"},{"key":"ref_102","doi-asserted-by":"crossref","unstructured":"Chadda, K.R., Roberts, S.A., Lugg, S.T., Faniyi, A., Faustini, S., Webster, C., Duffy, J., Hewison, M., Shields, A., and Richter, A.G. (2024). Vitamin D deficiency and duration of COVID-19 symptoms in UK healthcare workers. Front. Med., 11.","DOI":"10.3389\/fmed.2024.1494129"},{"key":"ref_103","first-page":"357","article-title":"Association Between Vitamin D Deficiency and Long COVID Symptoms in Post-Hospitalized Patients: A Prospective Cohort Study","volume":"15","author":"Amin","year":"2025","journal-title":"Eur. J. Cardiovasc. Med."},{"key":"ref_104","doi-asserted-by":"crossref","unstructured":"Ao, T., Kikuta, J., and Ishii, M. (2021). The Effects of Vitamin D on Immune System and Inflammatory Diseases. Biomol. Mediterr. J. Rheumatol., 11.","DOI":"10.3390\/biom11111624"},{"key":"ref_105","doi-asserted-by":"crossref","first-page":"7","DOI":"10.31138\/mjr.33.1.7","article-title":"The Immunomodulatory Properties of Vitamin D","volume":"33","author":"Athanassiou","year":"2022","journal-title":"Mediterr. J. Rheumatol."},{"key":"ref_106","doi-asserted-by":"crossref","unstructured":"Fakhoury, H.M.A., Kvietys, P.R., Shakir, I., Shams, H., Grant, W.B., and Alkattan, K. (2021). Lung-Centric Inflammation of COVID-19: Potential Modulation by Vitamin D. Nutrients, 13.","DOI":"10.3390\/nu13072216"},{"key":"ref_107","doi-asserted-by":"crossref","first-page":"240","DOI":"10.7150\/ijms.103260","article-title":"Comparison of the role of vitamin D in normal organs and those affected by COVID-19","volume":"22","author":"Peramaiyan","year":"2025","journal-title":"Int. J. Med. Sci."},{"key":"ref_108","doi-asserted-by":"crossref","first-page":"124","DOI":"10.18433\/jpps32518","article-title":"Association between vitamin D levels and inflammatory markers in COVID-19 patients: A meta-analysis of observational studies","volume":"25","author":"Hopefl","year":"2022","journal-title":"J. Pharm. Pharm. Sci."},{"key":"ref_109","first-page":"49","article-title":"Magnesium and vitamin D in long COVID syndrome; do they help?","volume":"36","author":"Wolf","year":"2024","journal-title":"Magnes. Res."},{"key":"ref_110","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1684\/mrh.2024.0535","article-title":"Combined oral supplementation with magnesium plus vitamin D alleviates depressive symptoms related to long-COVID: An open-label randomized controlled trial","volume":"37","year":"2024","journal-title":"Magnes. Res."},{"key":"ref_111","first-page":"3038","article-title":"Prevalence of vitamin D deficiency among patients attending a post-COVID-19 follow-up clinic: A cross-sectional study","volume":"26","author":"Galal","year":"2022","journal-title":"Eur. Rev. Med. Pharmacol. Sci."},{"key":"ref_112","doi-asserted-by":"crossref","unstructured":"Atieh, O., Daher, J., Durieux, J.C., Abboud, M., Labbato, D., Baissary, J., Koberssy, Z., Ailstock, K., Cummings, M., and Funderburg, N.T. (2025). Vitamins K2 and D3 Improve Long COVID, Fungal Translocation, and Inflammation: Randomized Controlled Trial. Nutrients, 17.","DOI":"10.3390\/nu17020304"},{"key":"ref_113","doi-asserted-by":"crossref","unstructured":"Fernandes, A.L., Sales, L.P., Santos, M.D., Caparbo, V.F., Murai, I.H., and Pereira, R.M.R. (2022). Persistent or new symptoms 1 year after a single high dose of vitamin D3 in patients with moderate to severe COVID-19. Front. Nutr., 9.","DOI":"10.3389\/fnut.2022.979667"},{"key":"ref_114","doi-asserted-by":"crossref","first-page":"19397","DOI":"10.1038\/s41598-022-24053-4","article-title":"Association between vitamin D supplementation and COVID-19 infection and mortality","volume":"12","author":"Gibbons","year":"2022","journal-title":"Sci. Rep."},{"key":"ref_115","unstructured":"National Institutes of Health (NIH), Office of Dietary Supplements (2025, December 10). Dietary Supplements in the Time of COVID-19\u2014Fact Sheet for Health Professionals, Available online: https:\/\/ods.od.nih.gov\/factsheets\/COVID19-HealthProfessional."},{"key":"ref_116","doi-asserted-by":"crossref","unstructured":"Petakh, P., Kamyshna, I., Halabitska, I., and Kamyshnyi, O. (2025). Effect of vitamin D supplementation on COVID-19 outcomes: An umbrella review of systematic reviews. Front. Nutr., 12.","DOI":"10.3389\/fnut.2025.1559471"},{"key":"ref_117","doi-asserted-by":"crossref","first-page":"623","DOI":"10.26502\/acbr.50170273","article-title":"Effect of Short Term High Dose Oral Vitamin D Therapy on the Inflammatory Markers in Patients with COVID 19 Disease","volume":"6","author":"Lakkireddy","year":"2022","journal-title":"Arch. Clin. Biomed. Res."},{"key":"ref_118","doi-asserted-by":"crossref","unstructured":"Cervero, M., L\u00f3pez-Wolf, D., Casado, G., Novella-Mena, M., Ryan-Murua, P., Taboada-Mart\u00ednez, M.L., Rodr\u00edguez-Mora, S., Vig\u00f3n, L., Coiras, M., and Torres, M. (2022). Beneficial Effect of Short-Term Supplementation of High Dose of Vitamin D3 in Hospitalized Patients With COVID-19: A Multicenter, Single-Blinded, Prospective Randomized Pilot Clinical Trial. Front. Pharmacol., 13.","DOI":"10.3389\/fphar.2022.863587"},{"key":"ref_119","doi-asserted-by":"crossref","unstructured":"S\u00fcmegi, L.D., Varga, M., Kadocsa, V., Szili, B., Stempler, M., Lakatos, P.A., N\u00e9meth, Z., and Tak\u00e1cs, I. (2025). Effect of Moderately High-Dose Vitamin D3 Supplementation on Mortality in Patients Hospitalized for COVID-19 Infection. Nutrients, 17.","DOI":"10.3390\/nu17030507"},{"key":"ref_120","doi-asserted-by":"crossref","first-page":"201912","DOI":"10.1098\/rsos.201912","article-title":"Vitamin D and COVID-19: Evidence and recommendations for supplementation","volume":"7","author":"Griffin","year":"2020","journal-title":"R. Soc. Open Sci."},{"key":"ref_121","doi-asserted-by":"crossref","first-page":"m4912","DOI":"10.1136\/bmj.m4912","article-title":"Covid-19: Evidence is lacking to support vitamin D\u2019s role in treatment and prevention","volume":"371","author":"Wise","year":"2020","journal-title":"BMJ"},{"key":"ref_122","doi-asserted-by":"crossref","unstructured":"Grant, W.B., Wimalawansa, S.J., Pludowski, P., and Cheng, R.Z. (2025). Vitamin D: Evidence-Based Health Benefits and Recommendations for Population Guidelines. Nutrients, 17.","DOI":"10.3390\/nu17020277"},{"key":"ref_123","doi-asserted-by":"crossref","first-page":"620","DOI":"10.1136\/jclinpath-2012-201301","article-title":"Vitamin D: A negative acute phase reactant","volume":"66","author":"Waldron","year":"2013","journal-title":"J. Clin. Pathol."},{"key":"ref_124","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/j.nutres.2014.12.008","article-title":"Does serum 25-hydroxyvitamin D decrease during acute-phase response? A systematic review","volume":"35","author":"Silva","year":"2015","journal-title":"Nutr. Res."}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/4\/634\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,17]],"date-time":"2026-02-17T05:15:10Z","timestamp":1771305310000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/4\/634"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,14]]},"references-count":124,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["nu18040634"],"URL":"https:\/\/doi.org\/10.3390\/nu18040634","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,14]]}}}