Residual antimicrobial coating efficacy against SARS‐CoV‐2

Aims This study evaluated the residual efficacy of commercially available antimicrobial coatings or films against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) on non‐porous surfaces. Methods and Results Products were applied to stainless steel or ABS plastic coupons and dried overnight. Coupons were inoculated with SARS‐CoV‐2 in the presence of 5% soil load. Recovered infectious SARS‐CoV‐2 was quantified by TCID50 assay. Tested product efficacies ranged from 3.0 log10 reduction at a 2‐h contact time. The log10 reduction in recovered infectious SARS‐CoV‐2 ranged from 0.44 to 3 log10 reduction on stainless steel and 0.25 to >1.67 log10 on ABS plastic. The most effective products tested contained varying concentrations (0.5%–1.3%) of the same active ingredient: 3‐(trihydroxysilyl) propyldimethyloctadecyl ammonium chloride. Products formulated with other quaternary ammonium compounds were less effective against SARS‐CoV‐2 in this test. Conclusions The residual antimicrobial products tested showed varied effectiveness against SARS‐CoV‐2 as a function of product tested. Several products were identified as efficacious against SARS‐CoV‐2 on both stainless steel and ABS plastic surfaces under the conditions evaluated. Differences in observed efficacy may be due to variation in active ingredient formulation; efficacy is, therefore, difficult to predict based upon listed active ingredient and its concentration. Significance and Impact This study highlights the formulation‐specific efficacy of several products against SARS‐CoV‐2 and may inform future development of residual antiviral products for use on non‐porous surfaces. The identification of antimicrobial coatings or films showing promise to inactivate SARS‐CoV‐2 suggests that these products may be worth future testing and consideration.