A laboratory study conducted at the University of Southampton demonstrated that norovirus was rapidly inactivated on copper and copper-alloy surfaces as a result of antimicrobial properties in the metal.
Synopsis of Methodology
For this study, murine norovirus (the “mouse version” of the virus) was used as a surrogate to human norovirus to test the effect of exposure to copper surfaces versus stainless steel surfaces. The study found that the rate of inactivation is also affected by temperature: the process occurs more slowly at 39 degrees F and is faster over a 2-hour period at 98 degrees F.
- In wet contact simulation testing, rapid inactivation of murine norovirus was observed on alloys containing more than 60% copper at room temperature but no reduction of infectivity on stainless steel was found.
- In dry touch simulation testing, all virus particles were inactivated on copper and copper nickel alloys within 5 minutes, within 10 minutes on bronze, 30 minutes on brass, and within 2 hours on nickel silver (copper nickel zinc alloys). No inactivation was observed on stainless steel.
- Increasing the viral load by 50 times did not affect inactivation times on copper alloys.
What is it?
- The norovirus (family Caliciviridae), the primary cause of gastroenteritis, is highly contagious and responsible for approximately 5-8 million deaths per year.
- The norovirus infects more than 267 million people worldwide annually, including 23 million in the US alone, resulting in up to 70,000 hospitalizations and 800 deaths per year
How is it contracted?
- The disease is usually contracted by ingestion of contaminated food, water, person-to-person contact and touching contaminated surfaces. Even cleaning cloths used to wipe contaminated surfaces can spread the infectious virus to other surfaces.
- Symptoms include vomiting, diarrhea and stomach cramping caused by inflammation of the stomach and intestines.
Where is it prevalent?
- Norovirus is responsible for many outbreaks, often seasonal, especially in closed environments such as on cruise ships and in healthcare facilities, schools, daycare centers and restaurants.
- Although healthcare facilities are the most commonly reported settings for norovirus outbreaks in the US, over 90% of diarrheal disease outbreaks on cruise ships are caused by this germ.
- In 2012 alone, the US Centers for Disease Control (CDC) reported over 3,000 cases of norovirus among cruise ships.
Copper and copper alloys are engineering materials that are durable, colourful and recyclable and are widely available in various product forms suitable for a range of manufacturing purposes. Copper and its alloys offer a suite of materials for designers of functional, sustainable and cost-effective products.
Copper and certain copper alloys have intrinsic antimicrobial properties (so-called ‘Antimicrobial Copper’) and products made from these materials have an additional, secondary benefit of contributing to hygienic design. Products made from Antimicrobial Copper are a supplement to, not a substitute for standard infection control practices. It is essential that current hygiene practices are continued, including those related to the cleaning and disinfection of environmental surfaces.