High-dose vitamin D versus placebo to prevent complications in COVID-19 patients: Multicentre randomized controlled clinical trial.

Background: The role of oral vitamin D3 supplementation for hospitalized patients with COVID-19 remains to be determined. The study was aimed to evaluate whether vitamin D3 supplementation could prevent respiratory worsening among hospitalized patients with COVID-19.

Methods And Findings: We designed a multicentre, randomized, double-blind, sequential, placebo-controlled clinical trial.