Respirator undersupply issues can be safely mitigated by applying UVC disinfection, as demonstrated in challenges with Geobacillus stearothermophilus spores and the SARS-CoV-2 virus

J Hosp Infect. 9 February 2022: S0195-6701(22)00037-8. doi: 10.1016/j.jhin.2022.01.021. Online ahead of print.

ABSTRACT

BACKGROUND: The global Covid-19 pandemic, accompanied by spikes in the number of patients in hospitals, has required significant quantities of respiratory protective devices (respirators), leading to shortages. Disinfecting used respirators by applying UVC light can allow safe reuse, reducing shortages. Here, UVC light is explored for respirator disinfection.

OBJECTIVE: To determine if UVC disinfection is applicable to allow safe and repeated reuse of respirators.

Methods: The UVC chamber (BioShift™, Signify, The Netherlands) equipped with LP mercury discharge lamps emitting at 254 nm, was used to determine the sporicidal and virucidal effects. Respirators exposed to spores and viruses were exposed to varying levels of UVC energy. Deactivation of biological agents was studied as well as the effects of UVC on particle filtration properties and respirator fit.

RESULTS: A 5 log reduction in the viability of G. thermophilus spores by a UVC dose of 1.1 J/cm² was observed. By simulating the spores present in the middle of the respirators, a 5 log reduction was obtained at a UVC dose of 10 J/cm². SARS-CoV-2 viruses were inactivated by 4 logs when exposed to 19.5 mJ/cm² UVC. In the event that UVC must be transmitted through all layers of respirators to reach spores and virus, a reduction of more than 5 log has been achieved using a UVC dose of 10 J/cm². Exposure to a six-fold higher UVC dose did not significantly affect the fit integrity or aerosol-filtering ability of the respirator.

CONCLUSION: UVC has been shown to be a gentle and effective means of respirator disinfection allowing reuse of UVC-treated respirators.

PMID:35150785 | DO I:10.1016/j.jhin.2022.01.021