HAMDEN — Dr. Daniel Barron is stepping in to help fill medical workers’ need for face masks.

Accompanied by his wife, Dr. Kristin Budde, and their 2½-year-old assistant, Everett, Barron, a resident in psychiatry at the Yale School of Medicine, decided to investigate how to make a mask that would fill the gap health-care workers are faced with during the COVID-19 crisis.

His concern was to make a mask according to the guidelines of the Centers for Disease Control and Prevention, including a wire across the top that can be fitted to the nose and a plastic face shield.

After figuring that out, he posted a YouTube video to teach others how to do the same. He makes clear in the video that while the masks — if made properly — conform to CDC guidelines, they are not intended to be an N95 rated or any form of rated mask.

Many people are pitching in to make the masks, part of what medical professionals call PPE — personal protective equipment. They don’t keep out viruses the way an N95 respirator will. Those are rated to block 95 percent of particles 0.3 microns or larger.

But the CDC says medical professionals can use the face masks, or surgical masks, if necessary.

“In settings where facemasks are not available, [health care professionals] might use homemade masks (e.g., bandana, scarf) for care of patients with COVID-19 as a last resort,” according to the CDC. “However, homemade masks are not considered PPE, since their capability to protect [health care professionals] is unknown. Caution should be exercised when considering this option. Homemade masks should ideally be used in combination with a face shield that covers the entire front (that extends to the chin or below) and sides of the face.”

Yale New Haven, Middlesex and other hospitals are accepting donated masks, but it’s important to make sure they are as well made as possible.

Stores like JOANN have set up stations where customers can buy the materials or put them together at the store. That’s where Barron got advice for how to make his own.

Barron said the wire across the top “is really important for maintaining a seal on your face.” He used a plastic sleeve from a photo album for the face shield, which he attaches to the mask with Velcro. He also made the mask in the form of a pocket so that a filter could be inserted.

“I wouldn’t want to mislead people,” he said. “This is obviously a homemade mask. It has not been evaluated.”

But with the plastic shield, if someone sneezed or coughed at you, sending droplets flying, “it would stop those or at least slow them down and that’s better than them going straight into your mouth and nasal passage.”

Barron got a crash course in sewing, buying a machine on Sunday. By Tuesday, he and Budde had made 35 masks. “I assumed it would be complicated, so I asked a lot of questions,” Barron said. One of the JOANN employees taught him “about thread, about cloth. He helped me choose a sewing machine,” he said.

Making a mask according to Barron’s design is a bit complicated.

“Being really mentally organized with a lot of pieces is hard,” he said. “You kind of get used to it after a while but the first few masks were really ugly. I broke a couple of needles.”

Sewers need to be careful not to stitch across the metal wire.

Barron uses 100 percent cotton muslin, though he said others are using old dress shirts or high-thread-count bedding would also work.

Cate Boeth, owner of Cate’s Sew Modern in Guilford, has been making masks and said, “The tighter the weave, the better.” Pillowcases with at least a 200 thread count per inch “gives you a start of a denser fabric that’s harder to penetrate.”

Middlesex Health has issued guidelines for how to make the masks, which call for two layers of double-weave cotton fabric, washed in hot water to prevent shrinkage of the mask.

“What is really stressful for people is feeling helpless, so giving people something to do, they feel in control on some level,” Barron said. “You create a positive change in your own life.”

Samantha Cullari, district manager for JOANN, said, “We’ve actually had the medical community, as well as local groups of crafters and sewers in the community,” come to the stores’ education studios. “You can come in and you can actually use our machines” or take the materials home, she said.

“Everything, from the fabric and the materials, are items that are recommended in the medical field,” Cullari said. “They’re not medical grade. They are accepted by the CDC in a time of crisis.”

Dr. Lisa Lattanza, chairwoman of the Yale School of Medicine’s Department of Orthopedic Surgery and Rehabilitation, said there are the effectiveness of homemade masks is still unknown.

“Will these masks filter at a high enough rate for a health care professional to wear when taking care of a COVID-19 patient? I think it’s unlikely,” she said. “I don’t think it’s zero and I think it’s a wonderful that people are doing this, and these masks will be used in some way. We can’t predict the future on what our need is going to be, so they could end up being a really important, critical piece.”

Lattanza said the more tightly woven the fabric is, the more likely it is to filter out small particles, but said, “There hasn’t been enough time to test the homemade masks. … When you have a lot of different people making things out of lots of different fabrics and patterns, there’s a wide range of variability in the mask.”

Cotton masks would be helpful by saving the medical-grade masks for use with Covid-19 and other highly contagious patients. They could be useful “perhaps in an ambulatory setting where people have already been screened for something.” They also may be useful to keep someone who may have been exposed by has not shown symptoms from “spreading it to each other when we’re working in close quarters.”

Lattanza said the PPE that is used in direct contact with patients must adhere to very precise specifications.

“The way we look at this in health care is there are levels of protection and we have to have the most highly vetted and the best protection when we’re dealing with patients that we know are infected or we suspect they’re infected and that’s not the circumstance that we would want to be using these homemade masks,” she said.

She said, however, the people making masks should continue. “We’re so grateful that people in the community are doing this and we don’t want them to stop doing it because we can’t predict that we might not need to use them beyond just the average person on the street. … People are walking around with bandannas and scarves around them, so the protection afforded by these homemade masks is going to be likely as good or better than that.”

One 2015 study compared cloth masks to medical masks and reported, “the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection.” The study found “Penetration of cloth masks by particles was almost 97% and medical masks 44%,” which is why Barron believes the plastic face shield is important.

The Department of Correction has converted five manufacturing shops, operated by inmates, to mass produce masks and produced 3,300 in the first two days of operation.

Yale New Haven Health System is accepting mask donations from 10 a.m. to 2 p.m. Monday through Thursday at its Regional Operations Center 600 Derby Ave., West Haven. They may also be mailed to the same address, with the notation “PPE Donation.”

Connecticut Media Group