UV-A radiation makes up for 95 per cent of the sun’s ultraviolet light and penetrates deep into the skin, all the way into the inner layers. While UV-C radiation has proved effective against the novel coronavirus, the wavelength does not reach the earth’s surface.
The study published in the British Journal of Dermatology compared all recorded deaths from COVID-19 in the continental US from January to April 2020 with UV levels for 2,474 US countries for the same time period. The analysis was thereafter repeated in England and Italy with the same results.
The only areas with insufficient levels of UV-B were included in the study.
Older studies have reported that rapid sunlight inactivation of SARS-CoV-2 in a lab setting, but more recent theory have concluded that UV-B radiation alone may not explain sunlight inactivation of the novel coronavirus.