The exchange of CASH MONEY is one way of spreading the virus.

[canetoad]

61. Good questions

Couldn't find anything about COVID-19 but this is about flu and seems quite relevant.

..snip
"We didn't study directly the transmission from banknotes to fingers and from fingers to upper respiratory tract," says study co-author Yves Thomas, director of the National Influenza Research Centre at Geneva University Hospital.

Studies suggest that the virus can only live on the skin for up to five minutes, which might be due to a variety of factors including temperature and pH of the skin, says Allison Aiello, an epidemiologist at the University of Michigan in Ann Arbor. That means, she says, that "even if it's on the bill, you are in much better shape if you can inactivate it on human skin." The best way to do that? Wash your hands frequently and do not touch your eyes, nose or mouth unless you have done so immediately before. Aiello says, "The reason I recommend frequent hand washing during influenza season is because the eyes, nose, and mouth are all membrane passages for self-inoculation with the flu virus which then makes it's way to epithelial cells, usually in the nose, throat and lungs where it replicates."

In addition, says Thomas, not all banknotes have the ability to shelter live viruses like the Swiss currency (Swiss franc) he and colleagues used in their study.

"The composition of banknotes is different from one country to he other," he says, noting that he has no clue whether the findings would translate to U.S. dollars or other international paper currency. But whether the money's dirty or not, the best way to avoid the flu, says Aiello, is to get the flu shot and scrub those paws frequently.

https://blogs.scientificamerican.com/news-blog/dirty-money-can-the-flu-be-passed-o-2009-01-05/