# In Vitro Differential Virucidal Efficacy of Alcohol-Based Disinfectants Against Human Norovirus and Its Surrogates

## TL;DR

This study compares how well alcohol-based disinfectants kill human norovirus and its surrogates, finding that acidic disinfectants are more effective.

## Contribution

The study is among few to use cell culture infectivity assays to evaluate hand sanitizers' effects on human norovirus and its surrogates.

## Key findings

- Acidic alcohol-based disinfectants completely inactivated HuNoV GII.17 within 30-60 seconds.
- Alkaline alcohol-based disinfectants did not inactivate HuNoV GII.17 even after 60 seconds.
- Disinfectants effective on surrogate viruses were not effective on HuNoV.

## Abstract

Human norovirus (HuNoV) is a major causative agent of foodborne illness and causes acute viral gastroenteritis. This study aimed to compare the virucidal efficacies of alcohol-based disinfectants against HuNoV and its surrogates for murine norovirus and feline calicivirus using a cell culture infectivity assay. Additionally, the study evaluated the validity of estimating virucidal efficacy on HuNoV from the results of virucidal efficacy on the surrogate virus. All disinfectants decreased the titer of each virus by >3 log10 and >4 log10 for an exposure duration of 30 s against murine norovirus and feline calicivirus, respectively. However, acidic alcohol-based disinfectants completely inactivated the HuNoV GII.17 strain for 30 or 60 s, whereas an alkaline alcohol-based disinfectant did not inactivate HuNoV GII.17 for 60 s. This finding indicates that the pH of alcohol disinfectants affects their virucidal effects against HuNoV, and acidity has a higher virucidal efficacy against HuNoV than alkalinity. Disinfectants showing virucidal efficacy against surrogates were not effective against HuNoV. Few studies have used cell culture infectivity assays to test the inactivating effects of hand sanitizers on HuNoV and its surrogates. Our study provides useful information for the development of disinfectants that are effective against HuNoV.