WASHINGTON - Someone with a cold may just have left a little drop of virus on
the light switch for you to pick up and infect yourself with, researchers found
in a real-life look at how colds get passed around.
Adults with runny noses leave the virus on about 35 percent of objects they
touch, such as telephones, door handles and television controls, the researchers
at the University of Virginia reported on Friday.
An hour after someone leaves a virus-infected droplet on a surface, it can be
picked up 60 percent of the time. And 24 hours later, 33 percent of the little
virus-laden droplets got onto a finger, the researchers told a meeting of the
American Society of Microbiology.
"Some adults left a few ... and some contaminated almost all of the sites
tested," said Dr. Owen Hendley, a professor of pediatrics at the University of
Virginia Health System, who led the study.
Although the study was funded by the makers of a disinfectant spray, Hendley
said it is far more important for people to remember to wash their hands.
"In order to get infected with the rhinovirus which causes essentially half
of the colds in adults and children, you have to get the virus on your fingertip
and then you stick in your own nose and your own eye," Hendley said in a
telephone interview.
His team wanted to study just how often this actually happens. So they put an
advertisement in the Charlottesville, Virginia newspaper seeking people with
colds.
They found 15 who were infected with rhinoviruses and asked them to spend the
night in hotel rooms.
The volunteers were asked to move around the room, sleep there, and get up
and spend two hours in the room before checking out. The researchers then asked
them to point to several places they had touched.
"Of the 150 sites that they pointed out to us, 52 had virus on them, which is
35 percent," Hendley said.
WATCH THAT TELEPHONE
"The common sites were the light switch, the hotel pen, faucet handles, the
door handle, the TV remote and the telephone," he said.
Two of the volunteers left no virus anywhere.
"Then there were three bad boys in there. We found virus on eight of the 10
sites which we sampled," Hendley said.
Other studies have shown that some people are "super-spreaders" of certain
infections.
"Whether they were real snotty or they were sloppy, I don't know," he said.
"We weren't in there watching them."
Then the researchers did a second phase.
"Because there is virus on a surface, that doesn't mean that you are going to
be infected with it," Hendley said.
The researchers had saved mucus samples from each volunteer. Several weeks
later, they put little drops of their mucus on surfaces in hotel rooms. Some
they let dry for an hour, some were left for 24 hours.
"Each person was exposed to his or her own mucus," Hendley said -- ensuring
they would not become ill again.
"We asked them to flip on a light switch or to dial the 9 on the telephone or
to hold the telephone handset," Hendley said.
Then they tested each volunteer's fingers. One-third of the time, a volunteer
picked up virus from touching an object in a room where the virus had been
drying for a full day.
In room where the virus had dried for an hour, the volunteers picked up virus
60 percent of the time.
"So your husband could leave it there for you and go to work and you could by
chance turn on a light and if you then put it in your nose and your eye and get
infected," Hendley said.
