From Our 2008 Archives
Toys in Doctors' Offices Are Germ Hotbeds
Refrigerator Handles, Light Switches, Phone Keypads Also Harbor Germs
Reviewed By Louise Chang, MD
Oct. 29, 2008 (Washington, D.C.) -- Bring your child's toys with you when visiting the pediatrician.
That's the advice of University of Virginia germ hunters who found evidence of cold viruses on one in five toys tested in waiting rooms.
The commercially available germ-killing wipes that are commonly used to clean the toys are "only modestly effective," says researcher Diane Pappas, MD.
"What was really discouraging was that two toys that tested negative before they were cleaned were positive afterward," she tells WebMD. "We don't know how, but the virus is somehow being transferred."
The findings were presented at a joint meeting of the American Society for Microbiology and the Infectious Diseases Society of America.
Doorknobs, Faucets Also Harbor Germs
In a separate study, Pappas' colleague Owen Hendley, MD, found that people with colds can also leave germs on doorknobs, refrigerator door handles, TV remotes, and bathroom faucets.
Hendley is a member of the team that showed two years ago that cold viruses can linger on surfaces in hotel rooms for 24 hours after an infected guest leaves, waiting to be caught by the next unsuspecting guest.
His new study involved 30 adults who were starting to show signs of the common cold. Nasal secretions from 16 of them tested positive for rhinovirus, which causes about half of all colds.
Participants were asked to identify 10 places in their homes they had touched in the preceding 18 hours, and DNA tests were used to look for rhinovirus.
"As anticipated from the hotel study, we found that people at home also deposit rhinovirus on the surfaces that everyone touches," Hendley tells WebMD. Six of 18 doorknobs tested were positive, as were eight of 14 refrigerator handles, five of 10 TV remotes, and eight of 10 bathroom faucets.
Salt and pepper shakers were germ hotspots; all three that were tested were positive.
Hendley notes that "just having the virus on the refrigerator handle or other surface is not a big deal. What we really wanted to know is whether an infectious virus could be transferred to fingertips, where it could then make its way to the mouth or nose and cause infection," he says.
To find out, the researchers deposited a tiny drop of six of the participants' own mucus on light switches, phone keypads, and other commonly used surfaces in the homes.
"What we found, which is pretty slick, is that one hour after the mucus dried, [the virus] was still infectious in 22% of cases. But by 24 hours, it was only infectious in 3% of cases, and by 48 hours, none of the samples had infectious virus," Hendley says.
"I was pretty happy that the infectivity of the virus decays over time," he says. "But if you come home and turn on a light switch that [a cold sufferer] just shut off, you'll have a pretty good chance of catching it."
The findings serve as a reminder that colds and the flu are not just spread by coughing or handshaking, says Paul Auwaerter, MD, of Johns Hopkins, who served on the committee that chose which studies to highlight at the meeting.
"They can also be spread by simply touching surfaces in the homes, even in the doctor's office," he tells WebMD.
Masks, Hand Sanitizers Can Help
So how can you protect yourself? The typical advice that's been passed from generation to generation is to wash your hands frequently during cold and flu season to avoid catching a bug. Now, a University of Michigan study suggests that wearing surgical masks and using alcohol-based hand sanitizers can also help.
The researchers studied about 1,000 students who lived in dorms during last year's flu season. They were divided into three groups for six weeks: one group wore masks, one wore masks and used hand sanitizers, and one did neither.
Results showed that the students in the two groups that wore masks were about 10% to 50% less likely to develop flu-like symptoms than those who used no preventive measures.
Researcher Allison Aiello, MD, says further study is needed to confirm the results. "Nevertheless, these initial results are encouraging since masks and hand hygiene may be effective for preventing a range of respiratory illnesses," she says.
SOURCES: 48th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC)/ Infectious Diseases Society of America (IDSA) 46th Annual Meeting, Washington D.C., Oct. 25-28, 2008. Diane Pappas, MD, University of Virginia, Charlottesville. Owen Hendley, MD, University of Virginia, Charlottesville. Allison Aiello, MD, University of Michigan, Ann Arbor. Paul Auwaerter, MD, Johns Hopkins.
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