Human Coronavirus 229E Remains Infectious on Common Touch Surface Materials

Warnes, Sarah L.; Little, Zoë R.; Keevil, C. William

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. Following application of a wet droplet to a copper surface, the predominant ionic species to dissolute from the metal surface is Cu(II), but reduction to Cu(I) and the Fenton reaction with oxidative intermediates from cell debris, molecular oxygen, or viral envelope could produce the highly toxic hydroxyl radical. ROS are generated in the natural course of coronavirus infection (42) and contribute to pathogenesis and apoptosis. Fujimori et al. (43) observed inactivation of influenza A H1N1 pandemic 2009 strain by Cu(I) iodide nanoparticles which involved hydroxyl radicals and resulted in degradation of hemagglutinin and neuraminidase viral proteins. They surmised that, although there was no exogenous hydrogen peroxide to fuel the Fenton reaction (equation 3), Cu(I) reacted with molecular oxygen to generate superoxide (equation 1) and, subsequently, hydrogen peroxide (equation 2) (which could also produce hydroxyl radicals via the Haber Weiss reaction) as follows: