Am J Infect Control . Effectiveness of 222-nm ultraviolet light on disinfecting SARS-CoV-2 surface contamination

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Am J Infect Control


. 2020 Aug 19;S0196-6553(20)30809-9.
doi: 10.1016/j.ajic.2020.08.022. Online ahead of print.
Effectiveness of 222-nm ultraviolet light on disinfecting SARS-CoV-2 surface contamination


Hiroki Kitagawa ¹ , Toshihito Nomura ² , Tanuza Nazmul ³ , Omori Keitaro ⁴ , Norifumi Shigemoto ⁵ , Takemasa Sakaguchi ³ , Hiroki Ohge ⁶



Affiliations

• PMID: 32896604
• DOI: 10.1016/j.ajic.2020.08.022

Abstract

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has emerged as a serious threat to human health worldwide. Efficient disinfection of surfaces contaminated with SARS-CoV-2 may help prevent its spread. This study aimed to investigate the in vitro efficacy of 222-nm far-ultraviolet light (UVC) on the disinfection of SARS-CoV-2 surface contamination.
Methods: We investigated the number of viable SARS-CoV-2 after UV irradiation (0.1 mW/cm²) at 222 nm for 10-300 s using the 50% tissue culture infectious dose (TCID₅₀). In addition, we used quantitative reverse transcription polymerase chain reaction to quantify SARS-CoV-2 RNA under the same conditions.
Results: One and 3 mJ/cm² of 222 nm UVC irradiation (0.1 mW/cm² for 10 and 30 s) resulted in 88.5 and 99.7% reduction of viable SARS-CoV-2 based on the TCID50 assay, respectively. In contrast, the copy number of SARS-CoV-2 RNA did not change after UVC irradiation even after a 5-min irradiation.
Conclusion: This study shows the efficacy of 222-nm UVC irradiation against SARS-CoV-2 contamination in an in vitro experiment. Further evaluation of the safety and efficacy of 222-nm UVC irradiation in reducing the contamination of real-world surfaces and the potential transmission of SARS-CoV-2 is needed.

Keywords: COVID-19; Disinfection; Environmental contamination; Far-UVC; SARS-CoV-2; Ultraviolet light.