While the world develops a vaccine against the virus that causes COVID-19, we look at the microbial properties of copper and check if indeed this metal can help us fight this massive outbreak.
COPPER 1 - MICROBES 0
Several laboratory tests have been developed to simulate contamination events under typical indoor temperature and humidity to measure the survival of bacteria on samples of copper and copper alloys such as brass and bronze.
This graph, published by the Copper Alliance, is what they call the kill curve for MRSA on copper, brass (80% Cu, 20% Zn) and nickel silver (55% copper, 27% zinc and 18% nickel) at 20 degrees Celsius and typical indoor humidity.
What is MRSA? It is a kind of bacteria that can cause skin infections such as boils or, in more vulnerable patients, more serious infections in wounds, bones, lungs and blood.
There was complete kill in less than 90 minutes on copper. The two copper alloys also showed good kill rates but the kill times were longer and dependent on copper content. Note that even after six hours, there is no reduction on the stainless steel coupon.
Copper has been shown to kill many other bacteria in tests such as this, and also to be effective against viruses such as Influenza A and Norovirus as well as fungi.
Trials in the U.S., Chile, Germany and Finland have supported these findings and verified that the effect is a continuous reduction in contamination.
WHAT ABOUT COVID-19?
At this time, it is reasonable to expect that the novel coronavirus will only live on copper surfaces for a few hours, as described on recent studies, including those by the National Institutes of Health (NIH), CDC, UCLA and Princeton University. The New England Journal of Medicine published a study on March 17th showing that the virus that causes COVID-19 is stable for several hours to days in aerosols and on surfaces, but only up to 4 hours on copper surfaces:
Copper is still the safest surface out in the world against this virus, and given that hospital-borne infections are costing the healthcare system as much as $45 billion a year—the copper upgrade cost is insignificant by comparison.
In the meantime, here is a list of EPA-recommended disinfectants for use against COVID-19.