Don't let your boss's cough ruin your day. (Bigstock)

Really fast. Only two to four hours after being deposited on a single doorknob or tabletop, viruses were present on more than half of workers and visitors in the building, as well as more than half of the surfaces they would commonly touch. According to research presented at the American Society for Microbiology's 54th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), this speedy spread can be cut down tremendously with the use of hand sanitizer and antiviral cleaning wipes.

“What we really learned is that the hand is quicker than a sneeze in the spread of disease,” lead author Charles Gerba of the University of Arizona said in a Q&A at ICAAC this morning. The initial doorknob was contaminated with a harmless, traceable virus chosen for its similarity to human norovirus (of cruise ship fame). Within a couple of hours, the pathogen had essentially infiltrated the building.

The worst viral hot spot was the break room. "That's the first thing you do when you go to work, you get a cup of coffee," Gerba said in the Q&A. But workers would be wise to make sure they're the first break room visitors of the day: It didn't take long for the communal area to become a viral minefield.

When people touch foreign surfaces, Gerba said, they pick up between 30 and 50 percent of the organisms on them. This isn't always a bad thing: Many microbiologists believe that it's beneficial for us to pick up other people's bacteria. But there's no such thing as a good norovirus.

Most of the colds, flu and diarrhea that humans experience are caused by bacteria we pick up from touching contaminated surfaces, Gerba said.  A typical adult touches their face once every three minutes, and this hand-to-mucus-membrane transfer is bad news.

But we have a weapon in the battle against office contagion: When just half of workers agreed to use hand sanitizer or antiviral cleaning wipes (the sanitizer whenever they went out in public and returned to the office, and the wipes once a day at their desk), the number of contaminated surfaces fell by 80 percent or more. So don't go bathing in Purell, but just remember: If someone in the building is sick, no surface is safe.