Keeping your distance from sick co-workers may not be enough to avoid contact with their germs: A new study shows that some viruses quickly spread through offices and other buildings, contaminating many surfaces in just hours.
In the study, the researchers placed virus samples on one or two surfaces — such as a doorknob or a tabletop — in an office building, hotel rooms and a health care facility. They used a virus called bacteriophage MS-2, which is harmless to people, but is about the same size and shape as the human norovirus, a highly contagious virus that causes diarrhea and vomiting. In other words, the researchers were able to trace how norovirus might spread through a building using a harmless virus.
Throughout the day, the researchers sampled 60 to 100 surfaces in the buildings, including light switches, bed rails, tabletops, coffee-pot handles, sink tap handles, doorknobs, and phone and computer equipment.
Within 2 to 4 hours, 40 to 60 percent of sampled surfaces in the buildings were contaminated with the virus, said study researcher Charles Gerba, a microbiologist at the University of Arizona. In the office, "the first area contaminated was the coffee break room," Gerba said. [Top 7 Germs in Food that Make You Sick]
In hotels, the virus traveled between rooms as workers cleaned the rooms. "If you hear someone coughing in the room next door, the virus they have may be in your room the next night," Gerba wrote in an email to Live Science.
Although the study only tested bacteriophage MS-2, this virus would be expected to travel in a similar way as norovirus and the flu, Gerba said.
In a second part of the study, cleaning staff and employees were given disinfecting wipes containing quaternary ammonium compounds (QUAT), which were used to disinfect commonly touched surfaces about once a day.
These disinfectants, along with proper hand hygiene, reduced the spread of the virus by 80 to 99 percent, Gerba said.
There are 60 different QUAT-based disinfectants that are certified by the U.S. Environmental Protection Agency (EPA) as effective against norovirus, the researchers said. QUATs are the most common disinfectants in products used by consumers, Gerba said. A list of all disinfectants (not just QUAT-based) that are registered as effective against norovirus is available from the EPA. A QUAT-based disinfectant that works against norovirus will also work against the flu virus, Gerba said. On the label, a long chemical name beginning in "alkyl" or ending in "chloride" is often a QUAT, he said.
"The results show that viral contamination of [surfaces] in facilities occurs quickly, and that a simple intervention can greatly help to reduce exposure to viruses," Gerba said in a statement.
To avoid catching norovirus, the Centers for Disease Control and Prevention recommends hand washing after using the toilet and before eating or preparing food. To clean contaminated surfaces after someone is ill, the CDC recommends using a chlorine bleach solution, or other disinfectant from the EPA list.
The study was presented today (Sept. 8) at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington, D.C.