In 1852, physician Victor Burq visited a copper smelter in Paris's 3rd arrondissement, where they used heat and chemicals to extract the reddish-brown metal. It was a dirty and dangerous job. Burq found the facility to be "in poor condition," along with the housing and the hygiene of the smelters. Normally, their mortality rates were "pitiful," he observed.
Yet, the 200 employees who worked there had all been spared from cholera outbreaks that hit the city in 1832, 1849, and 1852. When Burq learned that 400 to 500 copper workers on the same street had also mysteriously dodged cholera, he concluded that something about their professions—and copper—had made them immune to the highly infectious disease. He launched a detailed investigation into other people who worked with copper, in Paris and cities around the world.
In the 1854 to 1855 cholera epidemic, Burq could not find any deaths of jewellers, goldsmiths, or boilermakers—all those who worked with copper. In people in the army, he found that musicians who played brass instruments (brass is partly copper) were also protected.
In the 1865 Paris epidemic, 6,176 people died of cholera, out of a population of 1,677,000 people—that’s 3.7 people out of every 1,000. But of the 30,000 who worked in different copper industries, only 45 died—an average of around 0.5 per 1,000.
After visiting 400 different businesses and factories in Paris, all of which used copper, and collecting reports from England, Sweden, and Russia on more than 200,000 people, he concluded to the French Academies of Science and Medicine in 1867 that “copper or its alloys, brass and bronze, applied literally and pregnantly to the skin in the cholera epidemic are effective means of prevention which should not be neglected.”
Today, we have insight into why a person handling copper day in and day out would have protection from a bacterial threat: Copper is antimicrobial. It kills bacteria and viruses, sometimes within minutes. In the 19th century, exposure to copper would have been an early version of constantly sanitizing one's hands.
Since then, studies have shown that copper is able to destroy the microbes that most threaten our lives. It has been shown to kill a long list of microbes, including norovirus, MRSA, a staph bacteria that has become resistant to antibiotics, virulent strains of E. coli that cause food-borne illness, and coronaviruses—possibly including the novel strain currently causing the COVID-19 pandemic.
In a new preprint on SARS-CoV2, the strain that causes COVID-19, researchers at the National Institutes of Health virology laboratory in Montana sprayed the virus onto seven different common materials, reported MIT Technology Review. They found that it survived the longest—up to three days—on plastic and stainless steel, suggesting that surfaces in hospitals or steel poles on public transit could be places where people pick up the illness. Just a single droplet from a cough or sneeze can carry an infectious dose of a virus.
Bill Keevil, a professor of environmental healthcare at the University of Southampton in England who has previously received funding from the Copper Development Association, said that if copper surfaces were put in communal areas where many people gather, it could help reduce the transmission of respiratory viruses, like coronavirus 229E and also SARS-CoV2. Other than hospitals, he thinks the ideal locations for copper are public transportation systems, like buses, airports, subways. But he doesn't stop there: He would also like to see copper used in sports equipment in gyms, like weights, along with other everyday objects, including shared office supplies, like pens.
In the preprint, SARS-CoV2 "liked copper least," Antonio Regalado wrote in MIT Technology Review. "The virus was gone after just four hours."
In 2012, Schmidt and his colleagues ran a clinical trial in three hospitals, Memorial Sloan Kettering Cancer Center in New York City, Medical University of South Carolina, in Charleston, and Ralph H. Johnson Veterans Administration Medical Center, also in Charleston.
First, they figured out which items closest to a patient were the most contaminated with microbes—those were the bed rails, the nurse call button, the arm of the visitor chair, the tray tables, and the IV pole. Enveloping these items in copper reduced the presence of microbes by 83 percent. As a result, HAIs were reduced by 58 percent, even though the researchers had introduced copper to less than 10 percent of the surface area of the room.
We have other methods of killing bacteria and viruses to mitigate HAIs, including ultraviolet light and hydrogen peroxide gas. But both require a hospital room to be empty, and once sick people re-enter rooms, surfaces can easily be contaminated again. “Copper is continuously working 24/7 without supervision, without any need to intervene, and it never runs out,” Schmidt said. “As long as the metal's there, it's good to go."
So given how well it could work, for hospital infections and for health more generally, why isn’t copper everywhere? Why isn’t every door knob, every subway rail, every ICU room, made of copper? Why can we easily buy stainless steel water bottles, but not copper? Where are the copper iPhone cases?