Although alcohol-based disinfectants prevent certain strains of flu, they are “useless” against viruses – including the norovirus – that are not coated in lipid “envelopes,” the New York Times reports.

The chilling news is based on data from the U.S. Centers for Disease Control and Prevention. During the winter of 2006-07, researchers determined that facilities in which staff used alcohol-based sanitizers were six times more likely to have an outbreak of norovirus compared to those in which staff cleaned their hands using soap and water.

“This study suggests that preferential use of [alcohol-based hand sanitizer] over soap and water for routine hand hygiene might be associated with increased risk of norovirus outbreaks,” the researchers concluded.