Human Coronavirus 229E Remains Infectious on Common Touch Surface Materials
by American Society for Microbiology 2015-11-10
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Sarah L. Warnes, Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom
Zoë R. Little, Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom
C. William Keevil, Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom
"HuCoV-229E was rapidly inactivated on copper surfaces, with the inactivation rate being roughly proportional to the percentage of copper in the alloy. Alloys containing >90% copper inactivated 103 PFU coronavirus in <30 min,"
"The mechanism of bacterial death on copper surfaces is complex, involving not only direct action of copper ion on multiple targets but also the generation of destructive oxygen radicals, resulting in “metabolic suicide” (20). This was not observed for norovirus destruction on copper, presumably because of the lack of respiratory machinery (26). However, it appears that superoxide and hydroxyl radical generation may be important in the inactivation of coronaviruses on copper alloys but that inactivation on 100% copper surfaces is primarily due to the direct effect of copper ions."
"In our results, the Cu(I) chelator BCS protected coronavirus on brass surfaces, suggesting that Cu+ migrating from the metal is important in toxicity and supporting the Fenton reaction generation of hydroxyl radicals that was observed."
"We have observed previously (27) that exposure to copper surfaces resulted in significant morphological changes to nonenveloped norovirus, where possible disassociation of the capsid subunits exposed the viral genome to copper inactivation. In this study, we observed rapid damage, including clumping, breakage, membrane damage, and loss of surface spikes, to the coronavirus particles following exposure to copper, and some particles appeared smaller and seemed to have lost rigidity, folding up on themselves."
"Analysis of coronavirus genomic RNA from viruses exposed to copper and copper alloys revealed a nonspecific fragmentation of the entire genome that can also be observed at the gene level by the reduction in copy number of a small fragment of nsp4 proteins, and the extent of damage increased with contact time. We have observed that the reduction in the capsid integrity of norovirus allows access of copper ions to the genome inactivating the virus"
"The results from this study have shown that a relatively low concentration of enveloped respiratory viruses may retain infectivity on common hard surfaces for longer than previously thought and may present a real risk of infection to anyone who contacts a contaminated surface. However, human coronavirus 229E, an important pathogenic virus but also a surrogate for MERS coronavirus, which is structurally very similar, was rapidly inactivated on copper alloys. Inactivation results from a combination of direct copper ion attack and reactive oxygen species generation."
"There is now a large body of evidence from laboratory studies and small clinical trials to suggest that incorporation of copper surfaces could play a significant role in reducing infection transmission from contaminated surfaces."
20 Warnes SL, Keevil CW, 2011. Mechanism of copper surface toxicity in vancomycin-resistant enterococci following wet or dry surface contact. Appl Environ Microbiol 77:6049–6059.doi: 10.1128/AEM.00597-11
26 Warnes SL, Keevil CW, 2013. Inactivation of norovirus on dry copper alloy surfaces. PLoS One 8:e75017. doi:10.1371/journal.pone.0075017.
27 Warnes SL, Summersgill EN, Keevil CW, 2015. Inactivation of murine norovirus on a range of copper alloy surfaces is accompanied by loss of capsid integrity. Appl Environ Microbiol 81:1085–1091. doi:10.1128/AEM.03280-14.