Disinfection of SARS-CoV-2 by UV-LED 267 nm: comparing different variants.

UV irradiation is an efficient tool for the disinfection of viruses in general and coronavirus specifically. This study explores the disinfection kinetics of SARS-CoV-2 variants wild type (similar to the Wuhan strain) and three variants (Alpha, Delta, and Omicron) by 267 nm UV-LED. All variants showed more than 5 logs average reduction in copy number at 5 mJ/cm2 but inconsistency was evident, especially for the Alpha variant. Increasing the dose to 7 mJ/cm2 did not increase average inactivation but did result in a dramatic decrease in the inactivation inconsistency making this dose the recommended minimum. Sequence analysis suggests that the difference between the variants is likely due to small differences in the frequency of specific UV extra-sensitive nucleotide sequence motifs although this hypothesis requires further experimental testing. In summary, the use of UV-LED with their simple electricity need (can be operated from a battery or photovoltaic panel) and geometrical flexibility could offer many advantages in the prevention of SARS-CoV-2 spread, but minimal UV dose should be carefully considered.