Ultraviolet light (UV) acts as a powerful disinfectant and can prevent contamination of personal hygiene from various contaminated environments. The 222-nm wavelength of UV-C has a highly effective sterilization activity and is safer than 275-nm UV-C. We investigated the irradiation efficacy of 222-nm UV-C against contaminating bacteria and viruses in liquid and fabric environments. We conducted colony-forming unit assays to determine the number of viable cells and a 50% tissue culture infectious dose assay to evaluate the virus titration. A minimum dose of 27 mJ/cm2 of 222-nm UV-C was required for >95% germicidal activity for gram-negative and -positive bacteria. A 25.1 mJ/cm2 dose could ensure >95% virucidal activity against low-pathogenic avian influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV-2). In addition, this energy dose of 222-nm UV-C effectively inactivated SARS-CoV-2 variants, Delta and Omicron. These results provide valuable information on the disinfection efficiency of 222-nm UV-C in bacterial and virus-contaminated environments and can also develop into a powerful tool for individual hygiene.
Copyright: © 2023 Song et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.