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

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 log(10) 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 log(10) 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 log(10) HuNoV GEC for the neutralization (positive) control and increased 0·9 ± 0·2 log(10) 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.