Vaporized hydrogen peroxide (VHP) generator and room prepared for N95 respirator decontamination
Vaporized hydrogen peroxide (VHP) generator and room prepared for N95 respirator decontamination

Health care workers and first responders put their own health at risk every time they come face-to-face with someone who has – or may have – COVID-19. Often, the only thing between these workers and the virus is an N95 respirator. But a critically short supply of the masks could leave front-line workers unprotected, placing them, their families and other patients at risk of transmitting the virus.

The University of Louisville is offering a program to decontaminate used N95 respirators, boosting the supply of masks for local health care providers, first responders and community organizations such as nursing homes at no charge.

The N95 Decontamination Program, announced April 11 by Louisville Mayor Greg Fischer, will begin next  week, sterilizing up to 7,000 N95 masks per day using vaporized hydrogen peroxide (VHP). This process has been validated by Battelle Memorial Institute as a way to allow the masks to be reused safely by health care workers.

The respirators, which protect health care workers from up to 95% of small particles, including viruses, normally are discarded after a single use. However, the critical shortage of N95 masks amid the global COVID-19 pandemic has forced some health care workers to use masks longer than recommended or use other, less effective masks. Given the shortage, the CDC is not objecting to reuse of masks that have been decontaminated under the emergency circumstances, using processes that have been proven to be effective.

In her efforts to ensure a supply of personal protective equipment for the university, Cheri Hildreth, MBA, director of the UofL Department of Environmental Health and Safety, was investigating reports on various decontamination processes for N95 respirators. She heard about other institutions that were using VHP successfully.

“Clearly, VHP was looking like the real deal. I checked with Leslie Sherwood, as I thought she had a VHP generator for the university’s gnotobiotic laboratory,” Hildreth said. “When I started seeing the data on VHP, I said ‘we need to activate on this.’”

Leslie Sherwood, DVM, assistant vice president for research services and director of Research Resources Facilities at UofL, confirmed they did have the device, one of fewer than 100 in use across the country. The device vaporizes hydrogen peroxide that destroys bacteria and viruses in the air and on surfaces, and is used to decontaminate the contents of an entire room.

“We use the Bioquell VHP generator to disinfect rooms in the vivarium to keep our facilities and equipment very clean for our animals,” said Sherwood, who has orchestrated the decontamination project. “We also have used it for other decontamination needs that pop up. This has popped up.”

Sherwood and Hildreth assembled a team and set the project in motion in a matter of just a few days. They modeled the UofL decontamination process on one developed by Battelle using a Bioquell VHP generator following the 2014 Ebola outbreak and took cues from colleagues who developed a similar program at Duke University. Bioquell and Duke both have applied for Emergency Use Authorizations (EUA) from the U.S. Food and Drug Administration for the process. Battelle already has received an EUA from the FDA for the process.

So far, more than 30 organizations and facilities in Louisville, southern Indiana, Lexington and northern Kentucky have expressed interest in participating or applied on the project’s website.

“The ability to extend the life of our PPE eases the strain on access to a limited supply worldwide,” said Bob Van Burskirk, director of supply chain at UofL Health. “While our days-on-hand stock of PPE remains adequate, the safe reuse of select items ensures another level of safety for our front-line physicians and nurses.”

Participating facilities will be provided site-specific, dedicated collection containers for the used N95 respirators. Once filled, the containers are sealed, decontaminated, picked up by UofL staff members and brought to the Kosair Charities Clinical and Translational Research building on UofL’s Health Sciences Center campus. There, they are placed in a negative pressure air flow room in the lab with wire shelving strung with paper clips, each room holding 3,500 to 4,000 masks. The negative pressure air flow ensures that any air in the room is filtered and exhausted out of the building, not back into the hallway.

N95 respirator that has been decontaminated received tally marks on the strap
N95 respirator that has been decontaminated received tally marks on the strap

The used masks are hung and laid on wire shelves, arranged so that every surface is fully exposed to air, and the entire room is treated with VHP for 1-to-2 hours. The VHP is then allowed to dissipate, which takes another 4-to-5 hours.

After treatment with VHP, the masks are inspected for damage, staining or deformities, given a tally mark on the strap to indicate they have been decontaminated, and boxed to be returned to the same facility from which they were collected. Once the masks have 20 tally marks, they are discarded.

“When they are clean, we go through the quality assurance checks to make sure the elastic is not broken and there is no wear and tear,” said Steven Davison, DVM, assistant professor in Research Resources Facilities. “We have three rooms, so we can rotate groups of masks in each room, moving the VHP generator from one room to another.”

Each time a room full of masks is treated, biological indicators placed in the room are tested to ensure the VHP levels were sufficient to kill the virus, a step requiring an additional 24 hours. The entire process will take about 48 hours.

Davison said the staff members and UofL administrators have dedicated their own time to set up the rooms, test the process and provide administrative support to create the program.

“Our staff has been essential and very willing to help. They have the expertise in using the equipment. We couldn’t have gotten to this point without our staff, much less moving forward,” he said. “However, to keep it going, we will rely on a group of paid UofL employees who choose to participate and health sciences professional student volunteers.”

The program requires individuals to transport the used masks, perform the decontamination process and quality assurance checks and repackage and redistribute clean masks to health care providers. UofL employees who have training in biomedical safety procedures have chosen to participate, and protective equipment and safeguards are in place to protect them. In addition, UofL professional students in the Schools of Dentistry, Medicine, Nursing and Public Health and Information Sciences are eligible to volunteer to deliver the decontaminated N95 respirators to participating facilities. A sufficient number of staff and volunteers have signed up to help and are being trained to launch the program. If demand grows, more staff will be needed.

Sherwood said many individuals and departments throughout the university have come together to create the program in just a few weeks, including the School of Medicine, Speed School of Engineering, which provided logistics, the Department of Environmental Health and Safety, led by Hildreth, and the Executive Vice President for Research and Innovation’s office. In that office, Kevyn Merten, Ph.D., associate vice president for research and innovation, has navigated the legal, fundraising and participant details needed to get the program up and running.

“This is just one more example of the many members of the UofL community who have responded to urgent needs, working together and using our advanced research expertise and infrastructure to solve problems during this crisis,” said Kevin Gardner, Ph.D., executive vice president for research and innovation at UofL.

“Everyone that is involved in this really just wants to help the front-line health care providers,” Sherwood said.

The N95 Decontamination Program has been awarded a $50,000 grant from the One Louisville: COVID-19 Response Fund that will support operational costs of the program. However, since there is no charge to the hospitals and other participating organizations, donations are gratefully accepted to help further defray the costs of equipment and supplies.