[Vitamin D supplementation and COVID-19: expert consensus and guidelines]

After 12 months of viral circulation, the SARS-CoV-2 has infected millions of people around the world, leaving hundreds of thousands dead. With the lack of effective therapy and vaccination against COVID-19, focusing on the immediate repurposing of existing drugs gives hope of curbing the pandemic. Vitamin D is a possible candidate discussed in a high amount of publications. Randomized clinical trials show that vitamin D supplementation significantly reduces the risk of respiratory infections. There are also many evidences that hypovitaminosis D is an independent (and easily modifiable) risk factor for severe forms of COVID-19 and death. Vitamin D supplementation is a simple, safe and inexpensive measure, which is effective in correcting hypovitaminosis D found in 40-50% of the French population and in more than 80% of adults with COVID-19. In this position paper, we propose simple regimens (adapted to the pharmaceutical forms currently available in France) for vitamin D supplementation in adults with or without COVID-19.