Effect of UV and violet light on SARS-CoV-2

We performed an in-depth analysis of the virucidal effect of UV light on SARSCoV- 2 suspended in liquid medium. UV light was emitted by LEDs; in particular LEDs UV-C (278 nm), UV-B (308 nm), UV-A (366 nm) and violet (405 nm). An infectious titer of SARS-CoV-2 typically found in the sputum of COVID-19 patients was used to perform the tests using the qPCR (quantitative Polymerase Chain Reaction) approach. We verified that the virus can be completely inactivated by all the wavelengths employed with an increase of the dose going from UV-C to violet light. The long UV-wavelengths correspond to solar irradiation reaching the Earth surface. Our data extend previous results showing that SARS-CoV-2 is highly susceptible to UV light and can be used to support the reduction of incidence of SARS-CoV-2 infection seen in the summer season.