查看文章

The COVID-19 (coronavirus disease 2019) pandemic is having a colossal human, societal and economic cost that is encouraging individuals, physicians, collectives and authorities to re-evaluate the benefit/cost ratio of the various resources that could help us to better address the crisis—and limit the risk of its recurrence. In this context, we cannot ignore evidence in a recent ‘individual patient data’meta-analysis that vitamin D supplementation protects against acute respiratory infections (ARIs)[1]. In this meta-analysis of 25 randomised controlled trials (RCTs) for which the full data of almost 11 000 individual patients were available, subgroup analyses revealed that the benefit was observed in those who received frequent (eg daily) doses of vitamin D but not in those who received bolus doses, and that the effect was largest when vitamin D was given to individuals with vitamin D deficiency. Since then, several new RCTs have been published with mixed results, with some studies showing beneficial effects of vitamin D on ARIs while other did not. It is known that vitamin D stimulates innate immunity and modulates acquired immunity [2], explaining at least in part how vitamin D may fight against ARIs. Given that vitamin D deficiency is very common [3], especially during the ‘cold’season owing to a lack of sunlight exposure, and given that containment at home will prevent sunlight exposure for many people worldwide, even in spring/summer, we believe that vitamin D supplementation should be encouraged, at least in any individual with risk factors of vitamin D deficiency (eg obesity, old age, dark skin, wearing covering clothes, no sunshine exposure …