Copper metal has antimicrobial properties and can killgerms through direct contact.- The metal has been used to coat high-touch surfaces like door handles, surfaces in hospitals, and even personal items such as masks.
- However, copper isn't a cure-all, and it takes time and direct contact to destroy contaminants, so it might not always be the best solution for preventing viral infection, according to research.
As the US begins to tentatively return to business, despite the novel coronavirus still lurking among the population, any potential protection has become a hot commodity.
Copper metal, used in products such as door handles and key rings, is being touted as one such solution, advertised as killing the virus on contact.
But before you click "buy" on those Instagram ads for copper patches billed as "natural hygienic germ stoppers," it's important to distinguish between what copper is and isn't capable of doing against the virus.
It may help against germs in some instances, but it's not a panacea for prevention, since the coronavirus can still live on copper surfaces for hours. And it's certainly no substitute for other precautions, according to Dr. Miryam Wahrman, biology professor at William Paterson University and author of "The Hand Book: Surviving in a Germ-Filled World."
"From what we're dealing with now, I don't think there's a lot of evidence to support the usefulness of copper in terms of reducing infections," Wahrman told Insider.
"Germ-killing" ads include everything from copper discs and stickers to cell phone cases, bracelets and socks
There is a huge variety of copper products sold as "prevention tools," but they fall into four general categories.
There are wearables, such as face masks, but also tee-shirts laced with copper, and jewelry, which vendors claim "self-sanitize" if they come into contact with contagious particles.
Then there are "sanitizers," which are bars or discs made of or coated in copper. These are designed to be rubbed on your hands or other objects in order to sanitize them.
Touch-tools, the third category, can vary widely, but picture something that looks like bottle opener or key. You might use these to open doors, push buttons, or even tap on touchscreens instead of directly interesting with those potentially germy surfaces.
Finally, there are copper-coated versions of everyday items you touch frequently, such as cellphone cases and door handles. The advantage of these over their ordinary counterparts is that germs (including coronavirus) can't survive as long on copper as on surfaces like plastic and other types of metal.
Copper can kill bacteria, but it's less effective against viruses
It's true that research has shown copper has antimicrobial properties — it can kill germs on contact in several ways, including by damaging the cell membranes, but is most effective against bacteria, Wahrman explained.
"Copper is good as an antimicrobial against certain types of bacteria but when it comes to viruses, that's a whole different ballgame because viruses are not living cells," she said.
An April 2020 study in the New England Journal of Medicine found copper is inhospitable for the novel coronavirus as well, as the virus has a much shorter lifespan on copper than on other surfaces such cloth, plastic, or even other metals.
That's important for environments where a lot of potential viral and bacterial particles are present, such as hospitals. A 2016 study found that using copper components in hospitals could help prevent patients from contracting other infections while hospitalized. According to the study, copper surfaces reduced the infection rate of patients by 58% (from 8.1% to 3.4%), and reduced the viral load on surfaces by 83%.
However, the study found the coronavirus can still survive as long as 4 hours on copper, and it could take as long as 45 minutes for copper to reduce even a substantial amount of the virus on a surface.
Most copper products do nothing more than lull you into a false sense of security, experts say
Touch-tools, which you can use to open doors, push buttons or otherwise interact with high-touch surfaces, might help by creating a barrier between contagions and your hand, but only if you keep the tool clean, too. If you're not careful to do that, this protective touch tool could simply be lulling you into feeling you're protected, when you're not.
"The positive thing is, you're touching fewer surfaces," Wahrman said. "But then you're going to come into contact with the part that's been touching surfaces when you put it back in your purse or your pocket. It's going to give you a false sense of confidence and won't occur to you that you've actually transferred germs to yourself and your home."
As an antimicrobial surface, copper could potentially still slow the spread of infection. But experts say it's highly unlikely that, even in that unlikely scenario, it wouldn't instantly kill coronavirus germs.
"The suggestion that you can rub these items on your hands and that's going to keep you healthy, that's not scientifically supported, especially for viruses," Wahrman said.
And face masks containing copper might be even less helpful, since in order for it to be effective, the copper needs to come into direct contact with the virus. Copper-infused cloth would only work if the virus penetrates the fabric, defeating the purpose of the mask in the first place.
"The face mask is a great barrier. They have a tight fiber so that they do block a lot of the viral particles and blocking them is key," Wahrman said. "If the viral passes through the mask, it's not going to interact with the metal anyway, so it's not going to make a difference."
For that direct contact to occur, items would need to be fully coated in copper across the entire surface. Even then, however, the virus wouldn't be eliminated instantly. There's an additional complication, too, with cleaning copper-coated objects, since typical cleaning products could interfere with the chemical properties of the metal that make it effective against viruses in the first place, according to research.
Copper might help on surfaces over time, but it can't prevent droplets direct from another person
None of these uses of copper address the most common form of contagious for the novel coronavirus, which is airborne infectious directly from person to person.
"The big problem with the coronavirus is that it travels in droplets from one person to another who inhales it and that's how most of the infections are happening. So there's no real way to get copper involved," Wahrman said.
So, while copper could have some promising applications, particularly in high-risk settings such as hospitals, it's not a cure-all for the average person, and it can't replace traditional disinfectants, hand sanitizer, or good old fashioned soap and water, according to Wahrman.
"The original advice that's tried and true is wash your hands with soap and water or use alcohol based hand sanitizer, and you've really reduced the risk and reduced the germ load," she said.
Wearing a mask, washing your hands frequently, and maintaining social distancing are still your best bet against slowing the spread of the virus, per the CDC's advice.
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