Where Has That Hand Been?

Don’t touch anything!
Researchers Track Virus Spread Within Public Buildings

Remember when your mother used to tell you, “Don’t touch anything” before you entered your aunt’s house—or just about any building?
Well, it turns out she was right, but not because you could break something. Rather, your probability of developing an infection from touching surfaces in public buildings—even health care facilities—is about 80%, according to Charles Gerba, PhD, a microbiologist at the University of Arizona in Tucson.

Within two to four hours of placing a benign virus on one common surface, such as a doorknob or table top, the virus could be detected on 40% to 60% of workers and visitors, as well as various other surfaces throughout the building (abstracts K-1722, 152a), according to Dr. Gerba who presented two studies at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).

“Every time you touch one of these surfaces, you are picking up 30% to 40% of the organisms on that surface,” Dr. Gerba explained, adding that adults then touch their faces about once every three to four minutes, and children do so more frequently, which is how they would become infected from a virulent virus.

“We learned that the hand is quicker than the sneeze in the spread of disease,” Dr. Gerba said.

The researchers used a tracer virus—a virus they could track, but would not infect animals, plants or people—and placed it in various buildings, including health care facilities, office buildings and hotels.
The virus was placed on one to two commonly touched surfaces (door knob or table top) at the beginning of the day. After two to eight hours, they sampled 60 to 100 fomites, surfaces capable of carrying infectious organisms (light switches, bed rails, table tops, countertops, push buttons, coffee pots handles, sink tap handles, door knobs, phones and computer equipment), for the virus.

“Within two to four hours between 40% and 60% of the fomites sampled were contaminated with virus,” Dr. Gerba said.

The first area to be contaminated: the coffee break room. “You definitely want to be the first one in that area [everyday],” he said. “
That turned out to be a hot spot.”

In the intervention phase, 50% of the cleaning personal and employees agreed to use quaternary ammonium disinfectant-containing wipes and alcohol hand sanitizers. The number of fomites on which virus was detected was reduced by at least 80% and the concentration of virus reduced by 99% or more.

“What surprised us is only half the people agreed to use hand sanitizers and disinfectant wipes, yet, there was a dramatic effect on the spread of the viruses,” Dr. Gerba said.

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