You're more likely to pick up germs from a keypad than a used tissue.
If your sniffly friend wants to show you photos of her toddler on her phone, offer to hold her purse while she does the scrolling. Droplets of moisture containing cold-causing viruses get dispersed (and thus, neutralized) on tissues, fabrics and other soft materials but remain intact on metal, glass and the scratch-resistant polycarbonate of an iPhone. Cold viruses can live on these types of objects for up to 18 hours, says Jennifer Collins, MD, who has a private practice specializing in allergy, asthma and immunology and is affiliated with Beth Israel Medical Center in New York. In one 2007 study, when healthy people touched hard, smooth things like light switches, doorknobs and telephones that had been contaminated with viruses, 60 percent picked up the germs after one hour, and around 30 percent became infected at 18 hours. (Flu viruses tend to be heartier: Not only can they live from one to two days on hard, nonporous surfaces, but they can also stick around for 8 to 12 hours on soft, porous ones.)