Copper and its alloys brass, bronze, and copper-nickel have long been touted for their natural antimicrobial properties. Now, with the recent emergence of the global coronavirus pandemic, these materials have once again caught the media’s attention.
A browse through Copper.org reveals that the Copper Age preceded the Bronze Age and that “copper was the first metal to be hammered into bowls, around 4000 BC.” Meanwhile, the American Journal of Infection Control has emphasized that copper’s antimicrobial, germicidal, and “anti-infective” characteristics have been known since the Victorian era. Understandably, the 19th century saw copper coating on many hospital surfaces, remaining popular until stainless steel came to the fore during the 20th century. But now that COVID-19 has reached pandemic proportions, the pendulum might just swing back towards copper once more.
The infectious disease COVID-19 is caused by the novel coronavirus, SARS-CoV-2. It can be spread when an infected person sneezes and coughs, releasing tiny droplets that harbor the virus. Both the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have reiterated the importance of washing one’s hands and disinfecting frequently touched surfaces to prevent the transmission of COVID-19.
Researchers with the National Institutes of Health (NIH), the CDC, the University of California Los Angeles (UCLA), and Princeton University jointly discovered that the SARS-CoV-2 pathogen’s stability permits it to survive on certain surfaces, as published on the New England Journal of Medicine. The reason? Coronaviruses are resilient enough to survive on metal, glass, and plastic, as documented by the Journal of Hospital Infection. Additionally, the NIH has revealed that SARS-CoV-2 can survive up to 24 hours on cardboard and up to two or three days on plastic and stainless-steel surfaces. But perhaps the most encouraging news from the study was the finding that copper surfaces tended to degrade the novel coronavirus in about four hours.
Copper’s ability to disrupt COVID-19 should not be too far of a leap, given previous publication by the likes of the Health Environments Research and Design Journal that the material had also been proven to eliminate E. coli, influenza A, methicillin-resistant Staphylococcus aureus (MRSA), and norovirus germs.
Fast Company has also reported that “when influenzas, bacteria like E. coli, superbugs like MRSA, or even coronaviruses land on most hard surfaces, they can live for up to four to five days. But when they land on copper, and copper alloys like brass, they begin to die within minutes and are undetectable within hours…..No wonder that in India, people have been drinking out of copper cups for millennia.”
What is it about copper that makes it effective as an antimicrobial material? Insider points to the stuff’s effectiveness in disrupting the membranes that house a microbe’s DNA or RNA. In the case of the novel coronavirus, it destroys its RNA so that it cannot replicate itself in a host cell and thereby won’t be able to cause infection.
It is also believed that copper’s ability to act in place of other metals helps in its disrupting the normal biochemical pathways of the virus. As Dr. Michael D. L. Johnson of the University of Arizona College of Medicine explains, “by blocking the function of the protein, you block the function of the pathway,” thereby stopping it from continuing its infectious routes and cascades.
Imagine, then, a future with copper prevalent in public areas like offices, restaurants, schools, stores, and even in mail packaging. Picture your home having copper finishes, too, and not just amongst the kitchen and dinnerware.
Back in 2007, the United States Department of Defense’s Telemedicine and Advanced Technology Research Center (TATRC) had already wanted copper alloys fitted into hospitals, especially intensive care units, as cited on BMC Proceedings. Their data showed that a “coppered” hospital room registered 97-percent reductions in pathogens, lowering both hospital-acquired infections and patient mortality significantly.
Of course, copper oxidizes over time to create a green patina, as seen on the Statue of Liberty. But even in its oxidized state, the metal still poses a threat to pathogens. A solution may be to utilize copper alloys that won’t oxidize and change hues. Still, these alloys must contain more than 67-percent copper to truly be effective, as described by medical researcher Phyllis J. Kuhn in 1983. More tests still need to be run to see if oxidized copper will be as effective as its unoxidized counterpart against the novel coronavirus and any other future pandemic-level pathogen. Other challenges will be the sourcing of copper to fulfill a large future demand.
In any case, because the COVID-19 virus can linger on several other types of surfaces, the importance of proper hygiene is paramount, especially as it applies to the cleaning of everything in your home to help minimize the risk of pathogen transmission.