Veterinary college deploys decontamination system to allow reuse of N95 masks
The system uses vaporized hydrogen peroxide, and biological indicators are tested by the Virginia Tech Animal Laboratory Services to ensure that sterilization is complete.
In the wake of the COVID‐19 pandemic, the rapid depletion of personal protective equipment (PPE) used in the care of patients presents serious health and safety risks for health care workers.
To respond, a team of researchers, veterinarians, and animal care specialists at the Virginia-Maryland College of Veterinary Medicine has deployed a decontamination system that allows human health care workers to reuse scarce N95 respirator masks.
“We're giving people on the front line of this pandemic a little peace of mind that they actually have the supplies they need to protect themselves while they are saving lives,” said Margie Lee, a medical microbiologist and head of the Department of Biomedical Sciences and Pathobiology (DBSP) at the veterinary college.
Along with Lee, the team members include Karen Hall, animal resource manager, who led the deployment project; Pete Jobst, the college’s director of facilities; and Jennifer Zambriski, an assistant professor of epidemiology in the Department of Population Health Sciences and head of the Veterinary Teaching Hospital’s infection control team.
“Once we connected the right people who were committed to make it work, this happened in an incredibly short period of time,” said David Schabdach ’85, associate vice president for research and innovation and attending veterinarian and director of the Animal Resources and Care Division.
The decontamination system is housed on the Virginia Tech campus at the Center for One Health Research, a facility operated by the veterinary college in partnership with the Edward Via College of Osteopathic Medicine.
The system is helping to stretch supplies for health systems in the region, such as Carilion Clinic, the Roanoke-based nonprofit that comprises hundreds of clinics, hospitals, and specialist offices throughout Southwest Virginia.
Working closely with Carilion, the sterilizer’s manufacturer, and a team at Duke University that has used a similar system to sterilize PPE, Hall developed a decontamination protocol, which minimizes risk for workers and ensures that the N95 respirator masks are sterilized efficiently.
Used N95 respirator masks are gassed for 2.5 hours using concentrated hydrogen peroxide vapor to destroy bacteria, viruses, and other contaminants, including the novel coronavirus SARS-CoV-2. The system is able to sterilize up to 2,000 N95 respirators per 12-hour cycle, which includes the treatment and degassing step. Although each mask can be cleaned up to 20 times without degrading its performance, its elastic band can withstand only three cycles. As a result, a mask should not be cycled more than three times in order to preserve its ability to effectively fit a user’s face.
After being treated with vaporized hydrogen peroxide, biological indicators that are sterilized along with the masks are sent to the Virginia Tech Animal Laboratory Services (ViTALS), which tests the indicators to ensure that sterilization is complete. If no organisms grow, the respirator masks are considered safe for use by health care providers.
Developed by Lee, clinical assistant professor of clinical microbiology Tessa LeCuyer, and clinical laboratory scientists Diamond McClendon and Alex Shelor, the test looks for bacterial growth on the masks: Its presence is a sign that the sterilization process has gone awry.
“ViTALS has protocols in place for appropriate quality control and quality assurance for every test run in the lab to ensure the accuracy of results,” said Tanya LeRoith, the lab’s director and a clinical professor of anatomic pathology in DBSP. “We want to make sure that when we see no bacterial growth during the test, it is because the bacteria were killed by the sterilization process, not because there was a problem with the test. Our lab is accredited to ISO 17025 standards (the standards for diagnostic testing and calibration), so we know that the results can be trusted.”
Shortly after the veterinary college facility sanitized its first batch of N95 respirator masks, Virginia Gov. Ralph Northam announced that a similar decontamination system would be temporarily located at the Marching Virginians Center on campus. Though located on Virginia Tech property, that system is operated by the Virginia Department of Emergency Management and the West Virginia Department of Homeland Security and Emergency Management.
Having its own decontamination system has freed the veterinary college from needing to depend on other agencies, allowing greater control over the timing and transport of PPE. Moreover, the system will be of great help to the Veterinary Teaching Hospital as it continues to transition back to full services. Previously, PPE at the teaching hospital were disposed of after a single use, but now clinicians and technicians can reuse N95 respirator masks.
“We're going to have trouble finding PPE to take care of the animals and to support research projects that help combat COVID,” Hall said. “The decontamination system has multiple benefits beyond just its initial, intended use.”
Although the Commonwealth of Virginia has transitioned from “stay at home” orders to “safer at home” guidelines, epidemiologists still anticipate a second wave of the virus. The work undertaken by Hall and the other team members will be crucial to protecting the health and safety of the veterinary college community moving forward.
“I have a family member who was admitted to the ICU with COVID-19,” said Lee. “As an infectious diseases person, I see this pandemic getting a lot worse before it gets better. It's going to take a lot of people pulling together doing things they don't normally do to get us through this. This staff-driven endeavor is a great example.”
— Written by Sarah Boudreau, a student in the M.F.A. program in creative writing