Shelly Fritz and colleagues tested two homemade masks and found one showing potential for respirator protection for health-care workers.

When COVID-19 began to spread in spring 2020, Shelly Fritz started hearing that protective N95 respirator masks were in short supply. If they couldn’t obtain them, nurses were being asked to take unusual measures, such as reusing masks. Fritz was alarmed. “Reusing masks was not considered standard infection-control practice,” she said. “It created a lot of chaos.” But what was the alternative?

As shortages of personal protective equipment loomed nationwide, well-intentioned people across the country were making masks and dropping them off at hospitals. And yet, Fritz wondered, how do we know these masks truly protect the wearer? “We are a field that does not make decisions without evidence,” she said. “So, as nurses, we got creative.”

Fritz, an assistant professor of nursing at WSU Vancouver, worked with two colleagues—Marian Wilson of WSU Spokane and nurse anesthetist Shawn Brow—on a study to test how well homemade masks could work. The study is described their article, “Impact and Efficacy of Homemade Masks in a Pandemic,” which currently appears in American Nurse, the flagship journal of the American Nurses Association.

Researching the literature for what scant evidence could be found, the researchers asked local seamstresses to make an eight-layer cotton mask and a furnace-filter mask using common household materials. For the eight-layer cotton mask, “The materials we used and the number of layers seemed to be the sweet spot between breathability and potential protection,” Fritz said. The furnace-filter mask used a removable double layer of 3M Filtrete™ 1500 furnace filter inside. Fritz said the decision to use a furnace-filter in a face mask is similar to off-label use of pharmaceuticals.

The important step was to fit-test the homemade masks to be sure they would work. They enrolled 28 front-line health workers at Arbor Health in Morton, Wash., a community hospital where Fritz chaired the Board of Commissioners. For fit testing, the test subject dons a clear hood that fits over the head and is outfitted with a small opening near the neck. A sweet solution is sprayed through the small opening incrementally while the test subject performs a series of tasks, such as jogging in place and reading a passage. The mask is deemed protective against airborne transmission if it passes all fit testing steps—the person wearing the hood never smells or tastes the sprayed solution.

One of the two prototypes ensured a tight-enough seal to be effective: The furnace-filter mask, which includes a piece of household air filter inserted into a pocket for protection against airborne particles, a moldable wire nose/cheek bridge for sealing close to the face, and white shoelace ties with toggle to secure it in place. The researchers say these washable and reusable masks may be environmentally preferable to disposable masks and are usable in health-care situations.

“We are in no way claiming this is a respirator mask,” Fritz said, “because those have to go through FDA approval and testing. But 12 of the 28 participants passed our full 12-step fit testing—they never tasted the sweet solution at all. Clinically, you’d be cleared to go into a room where there is a risk from airborne particles.” Some of the masks tested were taped in place with surgical tape, which appeared to provide an extra barrier. Fritz believes with more frontline staff education on effective taping, the pass rate may have been higher.

“What this did tell us is that the mask has potential, and it definitely would work better than the cloth masks everybody is wearing,” Fritz said. “With a good fit, the homemade mask could provide enhanced protection beyond a regular cotton homemade mask or a single-layer surgical mask. It has the potential to be used as a stopgap where no other respirator is available.”

The pattern and instructions are freely available. “We’re putting it out there to help anyone who wants to make their own mask,” Fritz said.

The pattern is available on Fritz’s professional page on the nursing website: nursing.wsu.edu/people/roschelle-fritz or here.