Efficacy of an alcohol-based surface disinfectant formulation against human norovirus

Abstract

Aim To evaluate the anti‐noroviral efficacy of PURELL® surface sanitizer and disinfectant spray (PSS, an alcohol‐based formulation) using human norovirus GII.4 Sydney [hNoV, by RT‐qPCR and human intestinal enteroid (HIE) infectivity assay] and its cultivable surrogate, Tulane virus (TuV, infectivity assay), compared to sodium hypochlorite (NaOCl) solutions. Methods and Results PSS efficacy was evaluated in suspension and on surfaces [stainless steel (SS)] using ASTM methods. Results were expressed as log10 reduction (LR) of genome equivalent copy number (GEC, for hNoV, assayed by RT‐qPCR) and plaque forming units (PFU, for TuV, per infectivity assay). In suspension, PSS achieved a 2.9 ± 0.04 LR hNoV GEC irrespective of contact time (30 or 60 s) and soil load (2.5% or 5%). Under all treatment conditions, infectious TuV could not be recovered following exposure to PSS, corresponding to the assay limit of detection (3.1–5.2 log10 PFU). Infectious hNoV could not be detected in the HIE model after exposure to PSS. On SS and 2.5% soil, PSS produced a 3.1 ± 0.1 LR hNoV GEC, comparable to 500 ppm NaOCl for 60 s. With 5.0% soil, PSS produced a 2.5 ± 0.2 LR hNoV GEC, which was similar to 1000–5000 ppm NaOCl for 60 s. Conclusions PSS showed high anti‐hNoV efficacy by RT‐qPCR and in in vitro (TuV) and ex vivo (HIE) infectivity assays and performed similar to 1000–5000 ppm NaOCl for a 60‐s contact time on SS with added soil. Significance and Impact of Study hNoV remains a significant cause of morbidity globally, partly due to its resistance to numerous surface disinfectants. RT‐qPCR results from this study indicate PSS efficacy against hNoV is comparable to NaOCl efficacy. Infectivity assays leveraging TuV and the HIE model for hNoV support and confirm loss of virus infectivity. Collectively, these results indicate the product’s ability to inactivate hNoV quickly, which could be beneficial in settings having elevated risk for hNoV transmission.

The Efficacy of Commercial Surface Sanitizers against Norovirus on Formica Surfaces with and without Inclusion of a Wiping Step

“…1 to 3 ). While this is only the second set of findings for this particular product ( 14 ), the results for the other chemistries are consistent with previous reports ( 11 , 12 , 14 ). For example, NaOCl solutions containing 200 ppm free chlorine have previously been shown to be minimally effective against hNoVs after even a 5-min contact time ( 12 ).…”

“…This is supported by previous research in which deformation of hNoV-like particles occurred when exposed to alkaline conditions ( 32 , 33 ). Given previously observed synergistic antiviral effects of ethanol and high pH for hNoVs ( 14 , 34 ), the combination of ethanol and high pH is likely the primary driver of this product’s efficacy, resulting in further disruptions to hydrogen bonding in addition to stabilizing hydrophobic residues exposed during protein denaturation. ( 35 ).…”

“…In fact, the U.S. Centers for Disease Control and Prevention (CDC) recommends solutions of 1,000 to 5,000 ppm of sodium hypochlorite to inactivate hNoVs during a suspected contamination event ( 13 ). The use of such high-sodium hypochlorite concentrations is not tenable in many venues due to its corrosivity and/or potential to stain many hard and soft surface materials, a strong polarizing odor, potential health risks and hazards to the user, and susceptibility to reduced efficacy in the presence of organic material ( 14 ). In addition, the maximum allowable concentration of free chlorine for sodium hypochlorite-based surface sanitizers is 200 ppm when used on food contact surfaces (FCSs) ( 15 ).…”

Norovirus disease among older adults

“… 54 An in vitro experimental model by Costantini et al 56 using HIE showed complete suppression of norovirus GII strains in fecal specimens with as low as 50 parts per million (ppm) of chlorine solution. 56 Comparison of a commercial-grade alcohol-based surface disinfectant (‘PSS’) containing 29.4% ethanol (pH 12.6–12.9) with sodium hypochlorite solutions of various concentrations (1000–5000 ppm) was performed by Escudero-Abarca et al 57 In vitro assays (suspension and soil on stainless steel surface) consistently showed higher genome-equivalent copy number reduction for sodium hypochlorite as opposed to PSS, although PSS showed similar efficacy comparable to 1000–5000 ppm chlorine, when 60-s contact time was applied with high soil load. The authors suggested loss of attachment efficiency by viral particles and capsid disintegration due to the alkaline nature of the PSS as the mechanism of antiviral property.…”

“…The authors suggested loss of attachment efficiency by viral particles and capsid disintegration due to the alkaline nature of the PSS as the mechanism of antiviral property. 57 Sato et al 58 argued that the virucidal process involves protein denaturation rather than de-lipidation. Incubation of norovirus in alkaline solution-only, acidic solution-only, or alcohol-only did not demonstrate significant virucidal activity compared to control.…”