Copper Can Kill Germs - But There is a Catch
According to the World Health Organization (WHO), the coronavirus that causes COVID-19 can survive up to three days on plastic and stainless steel surfaces - which accounts for an enormous percentage of common "high-touch" surfaces in public.
As such, perhaps the findings of Dr. Charles Gerba, Professor of Microbiology at the University of Arizona (aka "Dr. Germ") should come as no surprise. Using levels of a biological molecule called adenosine triphosphate, or ATP, as an indicator, Dr. Gebra has conducted a number of studies to gauge the level of contamination of high-touch surfaces in a variety of public environments. In one such study, Dr. Gebra found a hazardous amount of germs (i.e., an ATP level of 300 or higher) with the following frequency of occurrences on specific types of items:
- 71% of gas pump handles
- 68% of mailbox handles
- 43% of escalator rails
- 41% of ATM buttons
- 40% of parking meters/kiosks
- 35% of crosswalk buttons
- 35% of vending machine buttons
Bacteria and viruses can persist on a wide range of surfaces. While frequent hand-washing and cleaning protocols can have a major impact on reducing germs, touching a gas pump, for instance, is unavoidable (unless stations go back to a full-service option - please make this happen) and circumvents even them most diligent cleaning procedure.
But there are some material-based solutions that can help with the conundrum of high-touch surfaces.
Copper Kills Germs
While it may live for days on plastics, wood, silverware, doorknobs, ceramics, glass, stainless steel, and other materials, the WHO also acknowledges that the coronavirus that causes COVID-19 only lives on copper for about four hours - less than a workday or night's sleep.
Copper has the ability to kill viruses and bacteria by disrupting the protective layers of certain microorganisms and interfering with their vital processes. This happens on contact - with no cleaning supplies. This is not new discovery; ancient Egyptians recognized the health benefits of copper versus other materials. However, this phenomenon of "contact killing" requires that the microorganism makes direct contact with copper.
According to Dr. Edward Bilsky at the Pacific Northwest University of Health Sciences, copper kills bacteria in the following ways:
- it disrupts bacterial cell membranes, damaging the DNA or RNA of the microbe;
- it generates oxidative stress on bacterial cells and develops hydrogen peroxide, which can kill bacteria cells; and
- it interferes with critical proteins.
Moreover, a recent study published in the Health Environments Research and Design Journal indicated that copper could kill the following:
- Methicillin-resistant Staphylococcus aureus (MRSA), a cause of staph infection
- Escherichia coli (E. coli) bacteria
- Influenza A
- Norovirus
Emerging research from the New England Journal of Medicine found that copper can also kill SARS-CoV-2, the coronavirus that causes COVID-19.
What is the Catch?
Aside from a likely cost premium for copper for door hardware, copper faucets, and the like, there is a major catch: many copper products receive a range of treatments that protect the metal and prevent oxidation, which turns copper to a greenish/bluish hue over time. However, copper has been shown to retain its beneficial antimicrobial properties after oxidation, which attests to the longevity of utilizing copper as part of a comprehensive approach to help thwart the spread of germs.
