Copper is very effective in the fight against bacteria and viruses. A number of studies have proven that copper surfaces destroy viruses in just a few hours compared to days on other more common surface materials. Copper is a natural antimicrobial that we have been using to our advantage for thousands of years — at first without even realizing its true power!
But how exactly does copper protect us against infectious microbes?
First, let’s start with bacteria. The research team at the University of Southampton in the United Kingdom explains that copper is effective against bacteria because it releases positively charged ions that act very quickly to destroy the bacteria’s DNA. Another important quality of copper is that its use can prevent mutation and antibiotic resistance by destroying plasmids — which can move between bacteria and develop into superbugs.
The super metal has also been found to neutralize a wide range of potentially fatal viruses on surface contact: infectious bronchitis virus, poliovirus, human immunodeficiency virus type 1(HIV-1), and other enveloped or nonenveloped single- or double-stranded DNA and RNA viruses. It can also destroy that human norovirus — an annoying and easily spread virus that is typically resistant to many cleaning products.
The answer to copper’s potency against viruses lies in its antiviral activity
Research indicates that brass and copper-nickel surfaces lead to a rapid inactivation of the human coronavirus. In the 2015 study, copper’s antiviral activity happened at varied time points. The virus was shown to be completely killed in less than 40 minutes on brass and 2 hours on copper nickels made from less than 70% copper. Copper nickels were seen to require a higher proportion of copper to reach the same viral inactivation quality as brass — 90% in nickel compared to just 70% required for brass. Stainless steel and nickel (that does not include copper) failed to present any antiviral action. And very mild antiviral activity was seen in the metal zinc.
When a virus comes into contact with copper, it is killed via the breaking apart of its genome.
The copper kicks into action with some irreversible damage — that virus is not coming back to life any time soon.
The scientists who delved into copper’s defences against the coronavirus 229E discovered that after exposure to copper the virus particles were smaller, less rigid and folded up on themselves. Interestingly, similar changes were not observed when recovering the virus particles from stainless steel surfaces.
The way in which copper kills viruses is complex. Ultimately the most important attribute is that copper ensures that microbes are continuously attacked and killed — and quickly. Similarly to how copper stops bacteria in its tracks, the super metal completely destroys the virus’ DNA. Effectively giving the virus no chance to adapt and develop any resistance that would make copper less effective against it in the future.
How effective at killing viruses is copper in comparison to other surfaces?
It’s very effective.
Many of our metals — copper, silver, iron, zinc, titanium — display some antimicrobial properties; copper is the best of the best and continuously works to kill microbes despite varied temperatures and levels of humidity.
In a 2015 study — which looked at how long the human respiratory virus 229E stays active on various surfaces — copper emerged as the best performing surface by far. Teflon, PVC, ceramic, glass and stainless steel all retained the virus particles for 5 days. Virus particles could still be identified on silicon rubber after 3 days. Copper, on the other hand, acted very quickly to eliminate all traces of the virus. The speed at which the virus particles were eliminated was directly proportional to the percentage of copper in the material. In the last month the US government also conducted some testing on the new coronavirus COVID-19 and they found that it could only survive on copper for 4 hours in comparison to 2 to 3 days on plastic and stainless steel.
Isn’t stainless steel a metal? If it’s not effective against microbes then why do we use it so often in kitchens?
Stainless steel is an iron-based alloy with a minimum of 10.5% chromium. The alloy typically includes carbon and nitrogen. Since iron itself doesn’t display strong antimicrobial properties — it’s alloys are even less capable of killing microbes. Iron and steel are significantly less expensive than other metals. The cost factor combined with the materials strength has led to its extensive use in construction.
Stainless steel is one of the most widely used surfaces in public spaces and kitchens around the world. However, many studies have shown that both bacteria and viruses can survive on the surface for a number of days. In order to keep stainless steel kitchen surfaces clean and free of microbes, strict hygiene practices must be constantly maintained. This is often impossible for public spaces.
Copper is the clear winner when it comes to surface inactivation of viruses
It’s pretty obvious that copper wins hands down in the competition for the most hygienic surface material. Although there is mounting evidence of the benefits of the use of copper surfaces, more large scale studies are needed before there is widespread acceptance and major decision-makers start to take action on the topic. An important milestone for copper researchers is the advocacy for antimicrobial copper by the ECRI institute, a world-leading research institute with influence on over 5000 healthcare organizations around the globe.
The answer to why we’re not yet making the best use of the incredible super metal is a topic for another day. There are a number of factors that have held back copper’s popularity since it reached its height in the industrial revolution.
What we are sure of is: copper is making a huge comeback.