More than two months into the coronavirus pandemic, wearing a cloth mask has become a way of life for many Americans. Public health experts recommend them to prevent the wearer from spreading any illness they may be carrying unknowingly, but many mask vendors are touting methods that offer extra protection.
Filters, which can minimize the virus particles that pass through the mask, have become a popular strategy, as have masks made with copper.
A microbiologist at University of Massachusetts Amherst, Phyllis Kuhn, PhD, invented a mask made of 99.5% pure copper mesh, according to a press release from the school. And two teen brothers in Raleigh, North Carolina, started a company called CopperSAFE, which has been so popular its product is now sold out. Major retailers like Amazon and Etsy also sell copper-infused masks.
How do copper masks work?
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Decades of research shows that bacteria and viruses that land on metallic copper surfaces are killed on contact. A March study in the New England Journal of Medicine found in a laboratory setting that copper can inactivate a high concentration of the novel coronavirus within four hours.
This recent finding is especially promising, according to Michael Schmidt, a professor of microbiology and immunology at the Medical University of South Carolina in Charleston, because the concentration of the virus as it spreads in the real world is usually much lower and can therefore be killed more quickly.
Schmidt, who's studied copper for years, told TODAY that the metal's ability to deactivate the virus is like a "grenade." The copper interacts with the oxygen in the atmosphere, which creates a highly reactive molecule, also known as a free radical, which then interacts with the virus and causes it to "literally explode."
How long this process takes depends on the amount of mucus surrounding the virus and the size of the explosion, but it usually happens "in real time," Schmidt explained.
Quarters, nickels and pennies all contain antimicrobial copper, he said, adding that if you're out of hand sanitizer, you can shake change around in your hand to rid get of any possible virus or bacteria.
According to Schmidt, many current retailers of copper masks are infusing fabrics like cotton and polyester with copper, so they still feel like normal cloth.
Are copper masks effective against the coronavirus?
Schmidt told TODAY that if reputable retailers start making these types of masks, it could be a "game changer." He added, "If we begin to incorporate copper masks into our strategy ... we may be able to short-circuit a second wave that's coming."
One 2010 study in the scientific journal PLOS One that looked at copper masks to reduce spread of influenza seems to support this idea.
"(Copper) masks may significantly reduce the risk of hand or environmental contamination, and thereby subsequent infection, due to improper handling and disposal of the masks," it concluded. (Note: The authors of the study worked at Cupron, a company that makes copper masks, and the company funded the work.)
But Dr. William Schaffner, medical director of the National Foundation for Infectious Disease in Bethesda, Maryland, is "dubious" that copper masks are better than regular ones.
While acknowledging copper's antiviral properties, Schaffner told TODAY that he was "less concerned about the specific materials" masks are made of than getting more people to wear them overall.
"We wish to inhibit the spray of the virus from getting to other people, and it's actually the physical barrier that's the most important rather than any concept of inactivation of the virus," he said. "Even if you touch the surface of the mask and do some hand hygiene, that addresses the problem."
Schaffner added that studying copper "in the laboratory" is different from "the real world," so it's hard to know under what settings and concentrations of the virus that a copper mask would kill it.
Should you buy a copper mask?
In addition to copper's antimicrobial benefits, these masks are also "durable," Schmidt said. "You can use it over and over again, and you can launder it."
Plus, because copper isn't an expensive material, these masks don't need to cost that much more than regular fabric ones. Microbiologist Phyllis Kuhn's mask, for example, sells for $25. The Copper Wear Mask company sells two for $29.99.
That said, Schmidt has concerns about the vast landscape of retailers making antiviral claims about their masks — as most have not put their products through the necessary research to prove it.
If you choose to buy a copper mask, Schmidt recommended the brand Cupron because it was the subject of the 2010 study and has been vetted.
For other vendors, you may consider contacting them before making your purchase to ask if their specific mask "has been validated," Schmidt said.
But even if the answer is no, the risk of buying a untested copper mask is no greater than that of a standard cloth face covering, he added.
This story first appeared on TODAY.com. More from TODAY: