Killing Flu Germs: What Works?

Will disinfectants help prevent flu in your family?

From the WebMD Archives

We’ve all seen news reports about the revolting germs that lurk on the surfaces of things we touch every day. So as flu season approaches, you might be preparing for battle, a battle against flu germs, a battle waged on doorknobs, and keyboards, and telephones, and other surfaces in your home and office.

But before you douse all your possessions with bleach, there’s one thing you should know: Experts say that you really don’t need to bother.

“Honestly, if you’re trying to prevent the flu, there’s just not evidence that spraying everything with disinfectant is going to make any difference,” says Christine Hay, MD, assistant professor at the University of Rochester Medical Center.

Why is that? “Outside of the body, the flu is a really wimpy virus,” Hays says.

Other flu experts agree. “There may be some transmission of flu through things like tabletops and doorknobs, but it plays a very minimal role,” says William Schaffner, MD, chairman of the department of preventive medicine at Vanderbilt University’s School of Medicine in Nashville.

Even so, there are still things you can do to protect yourself from influenza -- and kill some flu germs in the process. Here’s what you need to know.

How Are Flu Germs Transmitted?

While the flu virus may be a tough guy when it’s inside your body, in the outside world, it’s a frail weakling. The way the flu is structured, it simply isn’t very resilient.

The flu is nothing like some of the nasty gastrointestinal viruses, like the bane of all cruise ship vacationers, norovirus. “Some of those viruses can survive on an object for months and withstand cleaning with bleach,” Hay tells WebMD. “Influenza isn’t like that.”

There have been studies of how long significant amounts of flu germs can survive on surfaces. Estimates range from a few minutes up to 24 hours, depending on the type of surface. (It lives longest on hard surfaces.)

While 24 hours seems like a long time, experts downplay the significance. “I’ve looked at the data, and there just isn’t good evidence that environmental surfaces have a significant role in the transmission of the virus,” says Trish M. Perl, MD, assistant professor of medicine at Johns Hopkins Medical School in Baltimore. Instead, the flu seems to depend more on direct transmission from an infected person.

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Flu Prevention Tip: Clean Your Hands

If you’ve got the urge to clean away flu germs, the best place to start is with your hands.

“Covering your mouth and washing your hands are the two most important ways to stop the spread of the flu,” Perl tells WebMD.

What should you wash with? You might assume that antibacterial soap would be preferable, but that’s the not the case. First of all, flu is caused by a virus, not bacteria. Second, any type of soap will do.

“Time and thoroughness are what matters when it comes to washing your hands,” says Schaffner. “Not the type of soap.” It’s the scrubbing that counts. You’re not killing the virus with soap so much as dislodging it from your skin and sending it down the sink drain.

The CDC recommends that you wash your hands for the length of time it takes to sing “Happy Birthday” twice, about 15 to 20 seconds. Schaffner says that while 30 seconds would be ideal, he admits that this isn’t always possible.

“I’ve timed myself, and that can seem like a really long time,” Schaffner says. While it’s still a good goal, at the very least make sure that you’ve covered the surface of both hands and done it vigorously.

What about alcohol-based hand sanitizers? Flu experts are enthusiastic.

“I love the stuff,” Perl tells WebMD. She observes that one of its main advantages is that you can use it on the go, far away from sink. Just rub it in until it’s dry, she says, which usually takes just ten seconds or so.

“Gels are just as effective as soap and water at killing influenza virus,” says Schaffner. “We like both of them.”

Killing Flu Germs Around the Home and Office

Even if it may be an unlikely mode of transmission, it’s still conceivable that you could pick up the flu bug from a surface. So if you’d like, you can disinfect some of the areas in your home and office that are most likely to harbor flu germs.

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While flu germs can theoretically be spread by sheets or towels, it’s unlikely: Influenza can only live a few minutes on soft surfaces. (Still, it’s best to not share hand towels or anything else with someone who has the flu.) Influenza germs tend to last longest on hard surfaces, so you could focus on:

  • Doorknobs
  • Hand rails
  • Desks
  • Tables
  • Faucets
  • Computer keyboards and mice
  • Remote controls
  • Video game controllers
  • Elevator buttons
  • Toys

What type of cleaner should you use? “Really, any disinfectant will do the job,” says Schaffner. One common recommendation is a 1/2 cup of bleach mixed with a gallon of hot water.

Of course, if you have kids, all the precautions in the world may not be enough.

“Children are flu factories,” says Hay. “And with little kids, it’s almost impossible to stop them from sharing viruses with one another and bringing them home.” Even though day care centers may wash the toys and surfaces with bleach, it’s very hard to keep up.

What can a parent do? Aside from making sure your children get the flu vaccine, not a whole lot. Even hearty adults who haven’t been sick in decades are generally laid low once they have children, Schaffner says. Just consider it another cost of parenthood.

Keeping Perspective About the Flu

If you want to, you can spray your telephones with disinfectant and scrub your keyboards with bleach-soaked cotton swabs every day of flu season. But don’t get so focused on disinfecting surfaces that you neglect the three most important things you can do to keep flu germs out of your life.

  • Regularly wash your hands with soap and water or an alcohol-based sanitizer.
  • Cover your mouth when you cough, preferably with something other than your hand.
  • Get the flu vaccine every year.

Everything else is optional, flu experts say.

WebMD Feature Reviewed by Jonathan L Gelfand, MD on October 18, 2007

Sources

SOURCES: Curtis Allen, spokesman, CDC, Atlanta. Bridges, C. Healthcare Epidemiology, Oct. 15, 2003, vol 37: pp 1094-1101. CDC web site: “Stopping Germs at Home, Work, and School.” Christine Hay, MD, assistant professor, University of Rochester Medical Center, Rochester, N.Y. Trish M. Perl, assistant professor of medicine, Johns Hopkins Medical School, Baltimore. William Schaffner, MD, professor of medicine & preventive medicine, chairman of the department of preventive medicine, Vanderbilt University School of Medicine, Nashville. State of New York Department of Health web site: “What to Do? When Someone at Home Has the Flu.”

© 2007 WebMD, Inc. All rights reserved.

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