It may not be just that late fee that’s making you feel ill: Flu viruses can last for hours — even weeks — on plastic surfaces.
Flu and cold germs typically spread from person to person through coughing or sneezing. However, if you’ve touched something with germs on it, then touch your nose or mouth, you may also become infected.
And that’s where your wallet full of plastic comes in, says Mary Radmer, a registered nurse and infection control professional at Advocate South Suburban Hospital in Hazelcrest, Ill. According to the Center for Disease Control, the swine flu virus “can remain alive on inanimate objects or surfaces for two to eight hours,” she notes — and those inanimate objects include your credit cards. Sick cashiers can pass along germs if they handle your card during a transaction.
That eight-hour time frame is actually the good news. Some of the hardiest germs can successfully reproduce on plastic surfaces for weeks. Studies done in 2000 and 2001 showed that a few antibiotic-resistant germs could survive on plastic surfaces for three full months.
Keep in mind that germs live longest in wet environments. A droplet from a sneeze that lands on your card could contain thousands of germs — which could be transferred to other adjacent cards when you slide it back into your wallet, potentially contaminating cards you haven’t even touched. “The issue is moisture,” says Alesia Wagner, an osteopathic physician regional medical director for U.S. Healthworks in Southern California. “That’s how germs transfer from one surface to another.”
The water-retaining properties of mucus can help a germ survive hours — or even days — longer than it would without it. People who keep wallets in their pockets may also be fostering germs’ growth, since the warmth provides an ideal bacterial breeding ground.
Before you toss your credit card into quarantine, though, it’s important to note that plastic has significant advantages over cash, says Wagner. “More germs pass through cash than plastic,” she says. “That’s partly because many more people touch cash. It’s a volume issue.” (The safest form of money may actually be coins, since some metals have microbe-inhibiting properties.)
While you can cut down on the chances of a sick cashier passing along an illness through your card by swiping the plastic through a card reader yourself, you’ll likely be exchanging one risk for another, says Radmer, since punching a PIN number into a keypad poses its own problems. “Keypads are among the dirtiest things around,” she says. “If you’re using [a keypad] to enter a code or get cash back, you could be transferring germs through your hands,” she says.
Both Radmer and Wagner say that while wiping your cards down with an alcohol-based sanitizer might help prevent card-based germ transmission, people should keep everything in perspective. “To put this into context, I’d say that the most important thing you can do to keep yourself healthy is to wash your hands,” says Radmer. “When you’re out shopping, should you rush into the [department store] bathroom to wash your hands after every purchase? Probably not. But if you’re touching a soiled keypad, or if the person in line in front of you is coughing and sneezing, you should sanitize your hands with an alcohol-based preparation.”
Wagner agrees. “Germs are everywhere,” she says. “But for the most part, our immune systems are strong, and if we’re careful about washing our hands and using sanitizer, we won’t suffer any consequences.”
See related: If pandemic strikes, will banks, credit cards still work?