Just over two years since the World Health Organization (WHO) declared the SARS‑CoV‑2 outbreak a pandemic, we find on PubMed a surprising number of publications (256,087 articles as of June 19, 2022). A smaller but still significant number of these – 1,189 – regard “COVID‑19 and vitamin D,” a figure which amounts to an average of 1.5 publications daily. In comparison, 10,914 articles about “osteoporosis and vitamin D” have been published, although the first of these date to the beginning of the 1950’s.
In fact, from the beginning of the outbreak interest in vitamin D has been intense. Toward the end of 2020, this journal published a summary of the first handful of studies available at that time, and in particular those that provided the first data on the association between vitamin D levels and risk of SARS‑CoV‑2 infection.
Since then, a tremendous number of articles have been published. In this article, we will summarize the observations obtained from a meta-analysis performed by Italian experts regarding the association between vitamin D status and clinical outcomes in patients with COVID‑19. This meta-analysis is available on Open Access: we suggest that those interested in the topic read it in full. In this article we also offer a brief comment about the quality of the current evidence available on the benefits of vitamin D supplementation in these patients.