Not all wavelengths are created equal: disinfection of SARS-CoV-2 using UVC radiation is wavelength-dependent.

SARS-CoV-2 is mostly transmitted through close contact with infected people by infected aerosols and fomites. Ultraviolet subtype C (UVC) lamps and light-emitting diodes can be used to disrupt the transmission chain by disinfecting fomites, thus managing the disease outbreak progression. Here, we assess the ultraviolet wavelengths that are most effective in inactivation of SARS-CoV-2 on fomites. Variations in UVC wavelengths impact the dose required for disinfection of SARS-CoV-2 and alter how rapidly and effectively disruption of the virus transmission chain can be achieved. This study reveals that shorter wavelengths (254-268 nm) take a maximum of 6.25 mJ/cm over 5 s to obtain a target SARS-CoV-2 reduction of 99.9%. Longer wavelengths, like 280 nm, take longer irradiation time and higher dose to inactivate SARS-CoV-2. These observations emphasize that SARS-CoV-2 inactivation is wavelength-dependent.