The SARS-CoV-2 virus endures for days on plastic or metal but disintegrates soon after landing on copper surfaces. Here’s why
When researchers reported last month that the novel coronavirus causing the COVID-19 pandemic survives for days on glass and stainless steel but dies within hours after landing on copper, the only thing that surprised Bill Keevil was that the pathogen lasted so long on copper.
Keevil, a microbiology researcher at the University of Southampton (U.K.), has studied the antimicrobial effects of copper for more than two decades. He has watched in his laboratory as the simple metal slew one bad bug after another. He began with the bacteria that causes Legionnaire’s Disease and then turned to drug-resistant killer infections like Methicillin-resistant Staphylococcus aureus (MRSA). He tested viruses that caused worldwide health scares such as Middle East Respiratory Syndrome (MERS) and the Swine Flu (H1N1) pandemic of 2009. In each case, copper contact killed the pathogen within minutes. “It just blew it apart,” he says.
In 2015, Keevil turned his attention to Coronavirus 229E, a relative of the COVID-19 virus that causes the common cold and pneumonia. Once again, copper zapped the virus within minutes while it remained infectious for five days on surfaces such as stainless steel or glass.
“One of the ironies is, people [install] stainless steel because it seems clean and in a way, it is,” he says, noting the material’s ubiquity in public places. “But then the argument is how often do you clean? We don’t clean often enough.” Copper, by contrast, disinfects merely by being there.
Keevil’s work is a modern confirmation of an ancient remedy. For thousands of years, long before they knew about germs or viruses, people have known of copper’s disinfectant powers. “Copper is truly a gift from Mother Nature in that the human race has been using it for over eight millennia,” says Michael G. Schmidt, a professor of microbiology and immunology at the Medical University of South Carolina who researches copper in healthcare settings.
The first recorded use of copper as an infection-killing agent comes from Smith’s Papyrus, the oldest-known medical document in history. The information therein has been ascribed to an Egyptian doctor circa 1700 B.C. but is based on information that dates back as far as 3200 B.C. Egyptians designated the ankh symbol, representing eternal life, to denote copper in hieroglyphs.
As far back as 1,600 B.C., the Chinese used copper coins as medication to treat heart and stomach pain as well as bladder diseases. The sea-faring Phoenicians inserted shavings from their bronze swords into battle wounds to prevent infection. For thousands of years, women have known that their children didn’t get diarrhea as frequently when they drank from copper vessels and passed on this knowledge to subsequent generations. “You don’t need a medical degree to diagnose diarrhea,” Schmidt says.
And copper’s power lasts. Keevil’s team checked the old railings at New York City’s Grand Central Terminal a few years ago. “The copper is still working just like it did the day it was put in over 100 years ago,” he says. “This stuff is durable and the anti-microbial effect doesn’t go away.”