Preliminary evidence for seasonality of Covid-19 due to ultraviolet radiation

Abstract

The Covid-19 pandemic has spread across the world during early 2020, with unforeseen consequences. Beyond social measures and biomedical research, it is important to assess the seasonality of the epidemic to inform strategies, with limited available data in the short period of time between the March equinox and the June solstice. While the effect of multiple factors is being investigated, little attention has been paid to ultraviolet (UV) radiation, a key parameter of seasonal forcing. We review the effects of UV radiation, proposing it as a potential element of seasonality, and provide evidence from the current literature and scant, yet revealing, observations. Explicit consideration should be given to UV radiation for the seasonality of Covid-19 at high latitudes and altitudes, based on the SARS and MERS epidemics and coronavirus diseases, and not just the ‘warmer days’ of summer.