Providence St. Mary Medical Center has placed restrictions on what kind of face covering will be allowed in its hospital and clinics.
The change was instituted Monday across the Providence Health & Services network, said Kathleen Obenland, spokeswoman for St. Mary.
Continuing research has found not all face coverings are created equal when it comes to preventing virus transmission, and therefore Providence is banning gaiter masks, bandannas and masks with valves.
Also no longer allowed are those made of a porous fabric, such as a knit material, Obenland said.
While masking guidance has changed any number of times during the COVID-19 pandemic, recent studies are fine tuning the realities of masking.
According to a report published last month by the American Association for the Advancement of Science — a nonprofit group founded in 1848 — mandates for mask use in public during the pandemic, made worse by global shortage of commercial supplies, have led to widespread use of homemade face coverings and mask alternatives.
Although it’s widely assumed wearing such masks reduces the likelihood for an infected person to spread the disease, many of the recent mask designs have not been tested in practice, the report’s authors said.
In testing various types of coverings, scientists compared a variety of commonly available mask types and found some are nearly as effective as standard surgical masks, while some alternatives, such as neck gaiters or bandanas, offer very little protection.
Elizabeth Bowen, infection preventionist at St. Mary, said the science around masking — like the science around the coronavirus — is evolving.
That includes learning what different fabrics and other materials can and can’t do in stopping or reducing the spread of droplets from human mouths and nostrils.
The last two months have been especially intense in the study of effective masking and eye protection, hospital officials said, noting that the Centers for Disease Control and Prevention has been reliable for updating its recommendations as emerging evidence becomes available.
For example, the CDC said any masks with exhalation valves or vents should not be worn in the prevention of spreading COVID-19. “The purpose of masks is to keep respiratory droplets from reaching others to aid with source control,” the agency said in an August update.
Masks with one-way valves or vents allow air to be exhaled through a hole in the material, which can result in expelled respiratory droplets reaching other people.
Basically, Obenland explained, valve masks were originally manufactured and intended for construction work. They’re intended to keep harmful particles from entering the mask rather than leaving the mask.
Bowen also pointed to analysis by the University of Washington’s Institute for Health Metrics and Evaluation, considered the most important among mask studies.
The research center has provided projections on hospitalizations and deaths during the COVID-19 pandemic and performed an analysis earlier this summer of mask studies from the United States, China and Germany, according to a story in Hartford HealthCare.
The university’s findings echoed what experts have been saying: If 95% of people wear cloth masks when within 6 feet of others in public, it will reduce COVID-19 transmission by at least 30%.
And if every infected person transmits the virus to 30% fewer people, it improves the chances of subduing COVID-19’s spread in the United States, the article said.
A Duke University School of Medicine mask study examined 14 mask types. Participants were asked to repeat the same phrase into the box without a mask, then repeat with each mask. Every mask was tested 10 times, according to the Hartford story.
In the No. 1 spot for effectiveness at stopping airborne transmission is the fitted N95 medical masks with no valve, followed by three-layer surgical masks and various layered cotton mask styles.
The worst three face coverings are knitted, double-layer bandanna and the gaiter-style fleece masks, according to the study.
Indeed, neck gaiters can actually actually spread more of the virus than not wearing one at all, experts said, because the fleece fabric can break up large droplets of water into many smaller droplets, erasing all benefits of masking up to protect other people.
At St. Mary Medical Center or any of its clinics, masks will be provided to those who arrive without an approved one, Obenland said.