Efficacy of alcohol-based hand sanitizers against human norovirus using RNase-RT-qPCR with validation by human intestinal enteroid replication

Abstract

Successful human norovirus (HuNoV) cultivation in stem cell-derived human intestinal enteroids (HIE) was recently reported. The purpose of this study was to evaluate the anti-HuNoV efficacy of two alcohol-based commercial hand sanitizers and 60% ethanol by suspension assay using RNase-RT-qPCR, with subsequent validation of efficacy by HuNoV cultivation using the HIE model. In suspension, when evaluated by RNase-RT-qPCR, 60% ethanol resulted in less than one log10 reduction in HuNoV genome equivalent copies (GEC) regardless of contact time (30 or 60s) or soil load. The two commercial products outperformed 60% ethanol regardless of contact time or soil load, providing 2·2–3·2 log10 HuNoV GEC reductions by suspension assay. Product B could not be validated in the HIE model due to cytotoxicity. Following a 60s exposure, viral replication in the HIE model increased 1·9 ± 0·2 log10 HuNoV GEC for the neutralization (positive) control and increased 0·9 ± 0·2 log10 HuNoV GEC in challenged HIE after treatment with 60% ethanol. No HuNoV replication in HIE was observed after a 60 s exposure to Product A.