Copper's anti-microbial properties have long been known
Here is a study on its efficacy published last month.
Findings
Staphylococcus and Micrococcus were the two predominant genera present on touch surfaces, respectively occurring on 51,8% and 48,0% of control surfaces. In these facilities with relatively low bioburden, copper surfaces efficiently reduced the occurrence frequencies of three genera: Staphylococcus, Streptococcus and Roseomonas. Pathogenic species such as Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium were observed in very few samples. In addition, methicillin-resistant Staphylococcus aureus was observed on five control surfaces and one copper surface.
Conclusion
Contamination of healthcare facilities touch surfaces can be the source for the spread of bacteria through the institution. This in situ study shows that the frequency of the contamination as well as the specific bacterial population bioburden is reduced on copper alloy surfaces.
https://www.sciencedirect.com/science/article/pii/S0195670119304918