Sunlight separately from vitamin D is associated with a lower risk of death from COVID‐19

Abstract

Linked Article: Cherrie et al. Br J Dermatol 2021; 185:363–370.Many infectious diseases vary from season to season. We set out to discover whether sunlight might affect the risk of death from COVID‐19, and whether this might occur independently of vitamin D production.We carried out three independent analyses in the USA, in Italy and in England. We gathered data on deaths from COVID‐19 in the early months of 2020. In each country these were recorded in small geographical areas such as counties. We estimated total ultraviolet (UV) exposure from satellite data for each of these areas and excluded from analysis those locations where we predicted that the intensity and wavelengths of sunlight would make vitamin D.We constructed a mathematical model showing the link between UV and COVID death that took into account other risks of catching COVID (such as population density and the proportion of the population who have COVID), and then the risk of dying from COVID (such as age, ethnicity, air pollution, social deprivation). Having taken these factors into account, we found that in each country, higher levels of UV from sunlight are associated with a lower risk of dying from COVID‐19. This effect does not appear to be caused by vitamin D production and was most marked in England where the background UV levels are lower.We do not know how sunlight might reduce COVID death but UVA (longer wavelength UV) and its effect on the skin may be important. We think this needs to be studied and may be relevant to public health advice during this pandemic.