Abstract: (2022) 20:83 Cannata‑Andía et al. BMC Medicine https://doi.org/10.1186/s12916-022-02290-8 RESEARCH ARTICLE Open Access 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 Jorge B. Cannata‑Andía1,2,3,4*† , Augusto Díaz‑Sottolano2,5†, Pehuén Fernández6,7,8†, Carmen Palomo‑Antequera1,2,3, Pablo Herrero‑Puente1,2,3, Ricardo Mouzo9, Natalia Carrillo‑López1,2,4, Sara Panizo1,2,4, Guillermo H. Ibañez10, Carlos A. Cusumano11, Carolina Ballarino12, Vicente Sánchez‑Polo13, Jacqueline Pefaur‑Penna14,15, Irene Maderuelo‑Riesco16, Jesús Calviño‑Varela17, Mónica D. Gómez18, Carlos Gómez‑Alonso1,2,3,4, John Cunningham19, Manuel Naves‑Díaz1,2,4*†, Walter Douthat6,7,8†, José L. Fernández‑Martín1,2,4† and the COVID-VIT-D trial collaborators Abstract Background: Vitamin D status has been implicated in COVID-19 disease. The objective of the COVID-VIT-D trial was to investigate if an oral bolus of cholecalciferol (100,000 IU) administered at hospital admission influences the out‑ comes of moderate-severe COVID-19 disease. In the same cohort, the association between baseline serum calcidiol levels with the same outcomes was also analysed. Methods: The COVID-VIT-D is a multicentre, international, randomised, open label, clinical trial conducted through‑ out 1 year. Patients older than 18 years with moderate-severe COVID-19 disease requiring hospitalisation were included. At admission, patients were randomised 1:1 to receive a single oral bolus of cholecalciferol (n=274) or noth‑ ing (n=269). Patients were followed from admission to discharge or death. Length of hospitalisation, admission to intensive care unit (ICU) and mortality were assessed. Results: In the randomised trial, comorbidities, biomarkers, symptoms and drugs used did not differ between groups. Median serum calcidiol in the cholecalciferol and control groups were 17.0 vs. 16.1 ng/mL at admission and 29.0 vs. 16.4 ng/mL at discharge, respectively. The median length of hospitalisation (10.0 [95%CI 9.0–10.5] vs. 9.5 *Correspondence: cannata@hca.es; jorge.cannata@gmail.com; mnaves. huca@gmail.com † Augusto Díaz-Sottolano and Pehuén Fernández are second authors. † Walter Douthat and José L. Fernández-Martín are senior authors (two last authors). † Jorge B. Cannata-Andía and Manuel Naves-Díaz contributed equally to this work as corresponding authors. 1 Hospital Universitario Central de Asturias (HUCA), Avda. Roma s/n., 33011 Oviedo, Spain Full list of author information is available at the end of the article © The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit..