Decontaminating N95 masks with Ultraviolet Germicidal Irradiation (UVGI) does not impair mask efficacy and safety: A Systematic Review

Abstract

Background: Inadequate supply of filtering facepiece respirators (FFR) for healthcare workers during a global pandemic such as the novel coronavirus outbreak (SARS-CoV-2) is a serious public health issue. Aim: The objective of this review was to synthesize existing data on the effectiveness of ultraviolet germicidal irradiation (UVGI) on N95 FFR decontamination. Methods: We conducted a systematic review on UVGI in N95 FFRs by using Embase, Medline, Global Health, Google Scholar, WHO feed, and MedRxiv. Two reviewers independently determined study eligibility and extracted and verified predefined data fields. Original research reporting on N95 FFR function, decontamination, or mask fit following UVGI were included. Findings and Conclusions: Twelve studies were identified, comprising of 53 different UVGI intervention arms and 43 N95 FFR models. In all cases, FFRs maintained National Institute for Occupational Safety and Health (NIOSH) certification standards following UVGI. Aerosol penetration averaged 1.19% (0.70-2.48%) and 1.14% (0.57-2.63%) for control and UVGI arms respectively. Airflow resistance for the control arms averaged 9.79 mm H2O (7.97-11.70 mm H2O) vs 9.85 mm H2O (8.33-11.44 mm H2O) for UVGI treatment arms. All UVGI protocols employing a cumulative dose >20,000 J/m2 resulted in a 2 log reduction in viral load. A >3 log reduction was observed in 7 UVIG arms using a dose >40,000 J/m2. Impact of UVIG on fit was evaluated in two studies (16,200; 32,400 J/m2) and did not find evidence of compromise. Altogether, our findings suggest that further work in this area should use a cumulative UV-C dose of 40,000 J/m2 or greater, and confirm appropriate mask fit following decontamination.

Light-based technologies for management of COVID-19 pandemic crisis

“…Indeed, a recent in silico study demonstrated that for effective and fast decontamination one should consider the FFR shape besides the optical properties of the FFR model, which has to be determined at the UV-C specific wavelength [ 41 ]. Even though UV does not seem to affect the filtrating capacity of FFRs, it is important to note that high UV-C doses can lead to reduced tensile strength of its materials [ 42 , 43 ].…”

Biophotonic telemedicine for disease diagnosis and monitoring during pandemics: Overcoming COVID-19 and shaping the future of healthcare

“…As the incidence of COVID-19 increases exponentially worldwide, the demand for physicians, hospital beds, personal protective equipment, and isolation rooms to control the pandemic has overwhelmed the healthcare system [2,3]. In order to ensure the safety of healthcare professionals and comply with the WHO IPC strategies, telemedicine has become one of the main clinical practices.…”

Biophotonics for pandemic control: Large-area infection monitoring and microbial inactivation of COVID-19

“…In order to control the virus spreading and ensure the safety of healthcare workers, it is essential to develop ultraviolet (UV) lightbased innovations for extension of the lifetime of PPE (e.g. N95/SN95 respirators) [2], disinfection of environmental surfaces of rooms or objects, and microbial inactivation on food or biological tissues. These innovations are based on UV germicidal irradiation (UVGI), which typically uses UV-C irradiation including the 254 nm wavelength for respirator decontamination.…”