New research presented at a conference last week suggests that norovirus, the highly infectious winter vomiting bug, dies rapidly on surfaces made from copper and copper alloys. The finding, when corroborated by further studies, will likely add the sickness virus to a growing list of germs that copper is effective against.

The research is the work of Bill Keevil and Sarah Warnes of the University of Southampton in the UK, who found that norovirus is rapidly destroyed on surfaces made of copper and its alloys, with those comprising more than 60% copper being the most effective.

Worldwide there are more than 267 million cases of acute gastroenteritis every year due to norovirus.

The virus is highly contagious and causes vomiting and diarrhea. Having the bug is not generally dangerous: most people experience it as a short-lived unpleasant illness and recover within a day or two without having to see a doctor.

People contract norovirus from contaminated food and water, through contact with others, and also from touching contaminated surfaces such as door knobs and handrails.

Earlier this year, researchers in the UK reported how they developed a “vomiting robot” to help them find out how far norovirus germs travel when an infected person throws up.

The virus remains infectious while it sits on solid surfaces, and it is also resistant to many cleaning products.

In 2011, a survey presented at an American College of Preventative Medicine meeting even suggested that the preferential use of hand sanitizers over soap and water was linked to higher risk of outbreaks of norovirus in long-term care facilities.

There is no specific treatment or vaccine for norovirus, and when outbreaks occur they shut down hospital wards and care homes, which then have to undergo costly deep-cleaning, and there are also additional costs due to extra treatment and loss of staff working days.

In such facilities, frequently touched surfaces such as push plates, railings, tray tables, call buttons, door knobs and IV poles are known to serve as reservoirs for the spread of all kinds of bacteria, fungi and viruses.

The virus also impacts other establishments such as hotels and cruise ships, causing distress to guests and incurring business losses through damage to reputation, loss of working hours and disinfection costs.

Making frequently touched surfaces such as door handles and grab rails out of copper or one of its alloys could effectively deny the virus an important avenue of infection.

Keevil, a professor in the University’s Institute for Life Sciences, says in a statement:

“Copper alloy surfaces can be employed in high-risk areas such as cruise ships and care homes, where norovirus outbreaks are hard to control because infected people can’t help but contaminate the environment with vomiting and diarrhoea.”

The contamination model that Keevil and Warnes studied was designed to simulate fingertip-touch contamination of surfaces.

Several clinical trials around the world have already shown that copper and its alloys serve as an effective line of defence against many hospital acquired infections passed on through frequently touched surfaces.

According to the Copper Development Association, the market development, engineering and information services arm of the copper industry in the US, lab tests show that:

“… when cleaned regularly, antimicrobial copper surfaces kill more than 99.9% of the following bacteria within two hours of exposure: MRSA, Vancomycin-Resistant Enterococcus faecalis (VRE), Staphylococcus aureus, Enterobacter aerogenes, Pseudomonas aeruginosa, and E. coli O157:H7.”

As well as Keevil’s group in the UK, there are teams in Japan, South Africa and the US working in research labs and carrying out trials of the antimicrobial characteristics of copper.

The exact mechanism by which copper kills germs is still unknown but several theories exist and are being studied by international experts of the Global Mechanism Group.

In 2012 Keevil led a study published in the journal mBio, that showed copper may help slow the global spread of antibiotic-resistant infections by preventing horizontal gene transfer (HGT) in bacteria that can survive outside the body.

The United States Environmental Protection Agency (EPA) has registered more than 400 copper based alloys, such as brass and bronze, as public health antimicrobial products.

Written by Catharine Paddock PhD