Human Coronavirus 229E Remains Infectious on Common Touch Surface Materials

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

Inactivation of coronavirus on copper and copper alloy surfaces results in fragmentation of the viral genome, ensuring that inactivation is irreversible. Coronavirus was exposed to metal surfaces and recovered, and the positive-stranded viral RNA genome was extracted and purified. A one-step reverse transcriptase real-time quantitative PCR (RTqPCR) was performed to detect a 139-bp region of ORF1 within nonstructural protein 4 (nsp4). Virus that had been exposed to copper and brass surfaces demon- was applied to 1-cm 2 coupons of a range of brasses (A and B [early time points only]), copper nickels (C), and control metal surfaces that did not contain copper (stainless steel, zinc, and nickel). Virus was removed at various time points and assayed for infectivity as described in the text. Coronavirus was inactivated in Õ…40 min on brasses and 120 min on copper nickels containing less than 70% copper. Analysis of the initial 30 min of contact between virus and brasses ( Fig. 2B ) reveals an initial lag followed by rapid inactivation. Stainless steel and nickel did not demonstrate any antiviral activity, although mild antiviral activity was observed on zinc (this was significant only at 60 min [P Ï­ 0.046]). (D) The same inoculum was applied as 1 l/cm 2 , was dried immediately to simulate fingertip touch contamination, and was found to have inactivated the virus approximately 8 times faster. Error bars represent Ï® SEM, and data are from the results of multiple experiments. strated reduced copy numbers of this fragment with increasing contact times (Fig. 5A) . Comparison of the entire viral genome by agarose gel electrophoresis confirmed that nonspecific fragmentation occurred on copper and brass, with fragments becoming smaller with increasing contact time (Fig. 5B ).