In a report soon to be published, Penn Medicine’s Joel Gelfand, MD, MSCE, proposes using ultraviolet germicidal irradiation (UVGI) as a possible method for disinfecting respirators for the reuse of N95 respirators (masks) during the COVID-19 pandemic.
At the time of this post, N95 masks are currently considered critical supplies by the Centers for Disease Control and Prevention (CDC), reserved for health care workers and medical first responders. Across the healthcare industry, these masks are in limited supply.
When properly used, N95 masks filter out 95% of small particle aerosols and large droplets to substantially reduce a user’s exposure to the novel coronavirus. However, the manufacturers recommend that N95 masks be discarded after a single exposure.
In the wake of a shortage of masks, this has proved to be a source of great concern as providers have been forced to use substitutes that offer far less protection.
Antiviral Properties of UV Light
Short-wave ultraviolet (UV) light has been used as a disinfectant for more than a century. UV light kills or inactivates microorganisms by disrupting their DNA and replication.
Recent studies have demonstrated the efficacy of whole room UV as a disinfectant against coronaviruses, including MHV and MERS-CoV, and that UV light can be used to disinfect N95 masks against contamination with the influenza virus.
Ultraviolet Germicidal Disinfection of N95 masks
However, to date, few studies have evaluated UV light for SARS-CoV2, the coronavirus that causes COVID-19 disease.
Among the practices most familiar with the therapeutic use of UV light are psoriasis specialists, including Joel Gelfand, MD, MSCE, FAAD, at Penn Medicine. Dr. Gelfand, along with colleagues at Henry Ford Medical Center, has put forward a proposal for the possible repurposing of UV phototherapy devices as a platform for ultraviolet germicidal disinfection of N95 masks.
Using UV Light to Combat SARS-CoV-2
The proposal features a re-engineered prototype that was developed from a home phototherapy machine. This device is currently in use for the LITE study, a joint research effort from the National Psoriasis Foundation and dermatologists at the University of Pennsylvania, and other sites to investigating the effectiveness and safety of home-based versus office-based phototherapy for psoriasis treatment.
The prototype can irradiate 18 to 27 masks, depending upon the mask manufacturer, in approximately four minutes. Further study is needed to evaluate UV dose and general applicability of the prototype.
About Dr. Gelfand
The recipient of two Medical Professional Awards from the National Psoriasis Foundation, Dr. Joel Gelfand is the Vice Chair of Clinical Research and Medical Director, Dermatology Clinical Studies Unit at the Perelman School of Medicine, and Director of the Penn Psoriasis and Phototherapy Treatment Center. He has received multiple National Institute of Health grants to investigate psoriasis.
Dr. Gelfand’s report, Ultraviolet Germicidal Irradiation: Possible Method for Respirator Disinfection to Facilitate Reuse During COVID-19 Pandemic, will appear in the Journal of the American Academy of Dermatology this spring.