What Is a Mask Fitter? How to Make Device Featured in CDC Guidelines

Wearing a mask fitter could make face coverings up to 90 percent more effective at preventing the spread of COVID, according to research highlighted by the U.S. Centers for Disease Control and Prevention.

On Wednesday, the CDC published the results of experiments that suggest double masking—wearing a cloth mask over a medical mask—or knotting the ear loops of medical masks and tucking the excess material can "substantially" limit the transmission of COVID. If two people are both double masking or knotting and tucking masks, exposure to the virus is reduced by 96.4 percent, according to the agency.

The CDC report also drew attention to two recent studies that indicate mask fitters can boost protection by at least 90 percent against particles of the size considered most important for the spread of COVID. One study was a pre-print submitted to the website medRxiv on January 4, which means it has not yet been peer reviewed, while the other was published in JAMA Internal Medicine late last year.

On its Improve How Your Mask Protects You web page, the CDC advises people to ensure their coverings fit snugly to the face and have layers, as this prevents virus-carrying respiratory droplets from getting in and out.

The CDC now lists mask fitters or braces among the ways to improve fit. Other options include choosing a mask with a nose wire, or wearing a disposable mask underneath a cloth mask. It advises against layering two disposable masks as they will not fit closely enough to the face.

The guidance comes as variants of COVID spread around the U.S., particularly a more infectious one first identified in the U.K. Florida and California have emerged as hotspots for the variants.

What is a mask fitter?

Also known as a mask seal or brace, the frame-like device hooks over the ears and fits over the top of face coverings to improve fit. They work by preventing air from entering through open edges. Mask fitters can be used on cloth and disposable masks.

How to make a mask fitter at home

The Makerspace department at the University of Wisconsin-Madison has released details of how to make its Badger Seal mask fitter, which was found to be effective in the medRxiv study.

According to its creators, the Badger Seal costs less than $1 and takes five minutes to make. The video below explains how to make the mask fitter.

The Badger Seal is designed to be used with a three-layer disposable mask, a four-layer knit cotton cloth mask or a type of medical mask known as an ASTM Level II. It is important to ensure the mask material is breathable as it will fit more tightly than normal.

Makerspace states: "Warning: While our fitter seems to improve the seal of a face mask, it has not been tested for effectiveness in preventing illness, and you should use it at your own risk."

The Badger Seal can also be bought from manufacturers not affiliated with the university, listed on the Makerspace website.

For those with 3D printers, the National Institutes of Health has shared the details of how to print a personalized mask fitter created by Loma Linda University School of Dentistry in California and face-scanning app Bellus3D.

The NIH states on its website: "This design has undergone review in a clinical setting and has been found appropriate when fabricated with the printer type and materials specified."

Newsweek, in partnership with NewsGuard, is dedicated to providing accurate and verifiable vaccine and health information. With NewsGuard's HealthGuard browser extension, users can verify if a website is a trustworthy source of health information. Visit the Newsweek VaxFacts website to learn more and to download the HealthGuard browser extension.

covid, face masks, cdc,
A stock image of handmade fabric masks. The CDC has published a report on how to make masks more effective at preventing the spread of COVID. Getty