A few years ago, I wrote an article in cooperation with the Copper Development Association about the antimicrobial properties of copper. Most folks don’t realize that antimicrobial copper alloys are the only solid metal “touch surface” materials registered by the U.S. Environmental Protection Agency (EPA) to continuously kill more than 99.9 percent of bacteria associated with the most common hospital infections. According to the CDA, laboratory tests show that, when cleaned regularly, antimicrobial copper surfaces kill greater than 99.9 percent of the following bacteria within two hours of exposure: MRSA, VRE, Staphylococcus aureus, Enterobacter aerogenes, Pseudomonas aeruginosa, and E. coli O157:H7.
In fact, a growing number of hospitals and restaurants are using copper for frequently touched surfaces such as doorknobs, pulls and handles and faucet levers.
Which, today, demands the question:
“Can copper kill the coronavirus?”
That’s what I asked the experts at the CDA. They’ve yet to answer my emails or phone calls.
BUT … they’ve released a new statement on the subject.
How it Works
Science suggests that copper surfaces affect bacteria in two sequential steps. The first step is direct interaction between the copper and the bacterial outer membrane, which causes the membrane to rupture. The second is related to the holes in the outer membrane, through which the cell loses vital nutrients and water, causing a general weakening of the cell.
What We Know
I should preface the following by stating that there are various strains of the coronavirus, and the strain that causes Covid-19 is the the SARS-CoV-2 virus.
According to independent studies, at least one strain of the coronavirus (HuCoV-229E) appears to be affected by uncoated copper and copper alloy surfaces. (citation: https://doi.org/10.1128/mBio.01697-15). From the report: “Rapid inactivation of human coronavirus occurs on brass and copper nickel surfaces at room temperature (21°C).Brasses containing at least 70% copper were very effective at inactivating HuCoV-229E, and the rate of inactivation was directly proportional to the percentage of copper.”
There’s also been a U.S. government-funded study conducted by researchers at the National Institute of Health and the Center for Disease Control and Prevention (CDC) reporting that the SARS-CoV-2 virus, which causes the disease COVID-19, remained viable for up to 2 to 3 days on plastic and stainless steel surfaces vs. up to 4 hours on copper (citation: https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v1.full.pdf).
However, the CDA cannot shout from the rooftops that “Copper kills the coronavirus” because it has a stake in products such as doorknobs, handles, drawer pulls, etc. and they would risk claims of false advertising–not necessarily because the claim would be false, but because further testing is required to certify such product claims through the heavily regulated EPA.
In other words, the CDA is muzzled by red tape … but I’m free to make irresponsible claims!
Currently, copper alloy materials are registered by the EPA (Reg. Nos. 82012-1 to 6) to make public health claims against the six specific bacteria mentioned above. But, considering the limited evidence against SARS-CoV-2, further testing would be required to make those same claims against the new coronavirus.
Time will tell … but from what I’ve gathered, the prospect of copper’s effectiveness against the Big Bad Bug looks promising.
Look, I’m not suggesting that copper knobs are silver bullets or that swapping out your home hardware is a practical way to fight the current pandemic. After all, four hours on a surface is still a long time to spread infection. I’m simply pointing out an interesting aspect of copper that many people may not realize, and since we’ll be dealing with this plague for a while, and probably more plagues in the future, then maybe we can implement this knowledge into our building plans of tomorrow.
— Matt Weber