Forget retail therapy for some relief from that winter cold -- a study by Swiss scientists revealed on Wednesday that the flu virus can nestle and survive on banknotes for more than two weeks.
Scientists from Geneva's University Hospital were asked by a Swiss bank to carry out the study amid worries that a flu pandemic could be prolonged thanks to the millions of bank notes in circulation, Le Temps newspaper reported.
Between 20 and 100 million banknotes change hands in Switzerland alone each day, it said.
The researchers left small samples of the flu virus on used banknotes which were then left at room temperature. Although the virus only survived in most cases for a few hours, certain highly concentrated samples proved resistant for several days.
In the worst case, if the virus was mixed with human mucus on the banknote, it could survive for two and a half weeks, Le Temps said.
"This unexpected resilience of the virus suggests that this sort of inert, non-biological support should not be overlooked in pandemic planning," chief researcher Yves Thomas told the paper.
The team will now do further research to see how much of a factor banknotes might be in flu transmission, though Thomas stressed that the main risks remain airborne transmission and direct human contact.