The vitamin D for COVID-19 (VIVID) trial: A pragmatic cluster-randomized design.
Contemp Clin Trials. 2021 Jan;100:106176. doi: 10.1016/j.cct.2020.106176. Epub 2020 Oct 10.
Contemp Clin Trials. 2021.
PMID: 33045402
Free PMC article.
Clinical Trial.