Accessible UVGI Decontamination

Summary
Front line health care workers (HCW) are critical to the care and treatment of individuals with SARS-CoV-2 or COVID-19. There is a critical shortage of personal protective equipment (PPE), particularly filtering facepiece respirators (FFRs) (also called N95 masks) [1–3]. These are essential to protecting healthcare workers (HCWs) from any patients with the disease, while also protecting patients from contracting the disease from an HCW. Unfortunately, HCWs are faced with the harrowing decision to either not wear an essential mask, to construct a makeshift FFR with limited efficacy, or to re-wear a soiled mask - the majority are choosing the latter. This is an unprecedented world-wide shortage of life-saving equipment that our HCWs and beyond need in order to continue serving their communities. In addition to traditional HCWs, essential personnel working in pharmaceuticals, dentistry, custodial services, delivery services and law enforcement also require protection while they keep operations afloat. Distributed systems for N95 decontamination are needed to keep up with demand.

Ultraviolet germicidal irradiation (UVGI) has been demonstrated to be effective at quickly decontaminating FFRs for viruses like the novel SARS-CoV-2, and for multiple cycles of decontamination [4–6]. Nebraska Medicine has initiated an on-site UVGI system for N95 mask decontamination, but this system relies on existing UV decontamination equipment that many small community and rural hospitals do not have access to [7]. We document procedures to build a similar type of UVGI irradiation platform with off the shelf components from the hardware store and UVGI bulbs from biosafety cabinets that are ubiquitously found throughout academic research and industrial centers. In contrast to hydrogen peroxide vapor decontamination, which is currently in-process of being employed by a variety of companies, our system allows for on-site decontamination, removing the logistical challenge of shipping masks off-site to be decontaminated, therefore decreasing the cost and time required to decontaminate masks [8, 9]. We designed a UVGI system that is scalable and can be created for less than $50, on site, at the point of need, and leverages resources that are currently untapped and sitting unused in research facilities that have shut down during the SARS-CoV-2 pandemic. Hospitals can obtain this potentially life-saving UVGI resource with minimal funds, via collaboration between research facilities to obtain the otherwise limited availability UV-C meters and UVGI bulbs. Although our plans are illustrated using materials available in the U.S., this concept has global application. The ability for front line personnel to quickly disinfect PPE on-site during any healthcare emergency could be one important measure to reduce the spread of infectious diseases, especially when time and other resources are limited.

IMPORTANT FACTORS TO CONSIDER BEFORE DECONTAMINATING

1. 1. Higher UV required for higher humidity levels
• Important when considering condition of the mask - should be allowed to dry so water vapor from breathing not left on mask at the time of decontamination
• Decontamination should not be conducted in a particularly humid environment, otherwise mask irradiation should be adjusted accordingly [4]
2. 2. UVGI is less effective at decontaminating mask straps
• Recommend additional decontamination using a disinfectant wipe which is not an option for the filtering part of the mask [6]
3. 3. UVGI does not penetrate the interior of the mask [6]
• The recommended doses will only provide surface decontamination. This still presents major benefits to HCWs to prevent further spread of the virus between patients, and to themselves, and other HCWs
• Higher UVGI doses can allow for deeper penetration, but stability of the mask materials is then at risk and the number of decontamination cycles possible will be reduced
4. 4. CDC, NIOSH, and FDA currently do not recommend N95 decontamination [10]
• Decontamination during this unprecedented pandemic should be done carefully with the understanding that UVGI has not been firmly tested to rigorous standards but could help stop the spread of the virus caused from re-donning a contaminated mask

References
[ 1 ] Padilla M. ‘It Feels Like a War Zone’: Doctors and Nurses Plead for Masks on Social Media. The New York Times [Internet]. 2020 Mar 19 [cited 2020 Apr 5]; Available from: https://www.nytimes.com/2020/03/19/us/hospitals-coronavirus-ppe-shortage.html

[ 2 ] Goodnough A. Some Hospitals Are Close to Running Out of Crucial Masks for Coronavirus. The New York Times [Internet]. 2020 Mar 9 [cited 2020 Apr 5]; Available from: https://www.nytimes.com/2020/03/09/health/coronavirus-n95-face-masks.html

[ 3 ] Nierenberg A. Where Are All the Masks? The New York Times [Internet]. 2020 Apr 3 [cited 2020 Apr 5]; Available from: https://www.nytimes.com/article/face-masks-coronavirus.html

[ 4 ] Tseng C-C, Li C-S. Inactivation of viruses on surfaces by ultraviolet germicidal irradiation. J Occup Environ Hyg. 2007 Jun;4(6):400–5.

[ 5 ] Heimbuch B, Harnish D. Research to Mitigate a Shortage of Respiratory Protection Devices During Public Health Emergencies. Applied Research Associates; 2019 Sep p. 275. Report No.: HHSF223201400158C.

[ 6 ] Mills D, Harnish DA, Lawrence C, Sandoval-Powers M, Heimbuch BK. Ultraviolet germicidal irradiation of influenza-contaminated N95 filtering facepiece respirators. Am J Infect Control. 2018;46(7):e49–55.

[ 7 ] Lowe JJ, Paladino KD, Farke JD, Boulter K, Cawcutt K, Emodi M, Gibbs S, Hankins R, Hinkle L, Micheels T, Schwedhelm S, Vasa A, Wadman M, Watson S, Rupp ME. N95 Filtering Facepiece Respirator Ultraviolet Germicidal Irradiation (UVGI) Process for Decontamination and Reuse. 2020 Mar;19.

[ 8 ] Battelle cleared to sterilize N95 masks at max capacity, operate in other states to fight coronavirus PPE shortage | NBC4 WCMH-TV [Internet]. [cited 2020 Apr 4]. Available from: https://www.nbc4i.com/community/health/coronavirus/gov-dewine-fda-limits-battelles-ppe-mask-sterilizing-technology-to-only-10k-a-day/

[ 9 ] Battelle CCDS Critical Care Decontamination System for PPE Decontamination [Internet]. Battelle. [cited 2020 Apr 4]. Available from: https://inside.battelle.org/blog-details/keeping-the-human-connection-in-drug-delivery-device-development

[ 10 ] CDC. Coronavirus Disease 2019 (COVID-19) [Internet]. Centers for Disease Control and Prevention. 2020 [cited 2020 Apr 9]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html