Ask A Scientist: Do You Have to Change Your Toothbrush After You've Been Sick?

Do You Have to Change Your Toothbrush After You've Been Sick?
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The Scientist: Charles Gerba, Ph.D., professor of microbiology and environmental sciences at the University of Arizona

The Answer: Here's a myth we can put to bed: You don't have to throw out your toothbrush just because you have been sick. Whether you had the sniffles, a full-blown cold or even strep throat, you can keep cleaning your teeth with the same brush after you're feeling better.

Can germs live on your toothbrush? Yes, indeed they can, for a few hours up to a few days. And the moist environment provided by a recently rinsed toothbrush is rather hospitable to pathogens -- they usually last longer on wet bristles.

But as long as they're your own germs, you don't have to worry. You're not going to make yourself sick again if you use the same toothbrush after you've recovered. That's because you've built up antibodies over the course of your illness, so whatever is left on the brush will be wiped out upon entering your immune system. If you share your toothbrush, however, you could definitely make someone else sick.

That being said, you really shouldn't share your toothbrush with anyone anyway. If you want to disinfect your toothbrush, you can buy a toothbrush sanitizer that zaps germs with UV light -- but simply submerging it in boiling water will do the trick.

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Before You Go

10 Things You Probably Don't Want To Share
Bar Of Soap(01 of10)
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Despite the pervasive attitude that a bar of soap somehow cleans itself, the CDC recommends liquid soap over a bar when possible to cut down on sharing. A 1988 study found that germy soap isn't likely to transfer bacteria, but a 2006 study refuted that idea, citing soap as a source of continuous reinfection in dental clinics, Outside magazine reported. It could be because bars of soap don't usually dry all the way between uses, says Schultz, especially on the bottom, leading to an accumulation of bacteria, fungi and yeast that can be passed from person to person, he says. (credit:Getty)
Hats, Helmets, Hairbrushes And Combs(02 of10)
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Headwear is an obvious culprit when it comes to the spread of head lice, but so is making contact with sheets or pillows or couch cushions that have recently been used with an infested person, according to the CDC. (credit:Getty)
Antiperspirant(03 of10)
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There are two types of sweat, and one is smellier than the other. The odor comes from bacteria that break down the sweat on your skin. Deodorant, therefore, has certain antibacterial properties to stop the stink before it starts, explains Schultz. Antiperspirants, on the other hand, "are only interested in decreasing perspiration," he says, so they don't contain the same germ-killing powers. If you share a roll-on antiperspirant, you could transfer germs, bacteria, fungi and yeast from person to person, he says. Stop sharing, or switch to a spray. Even with a deodorant stick, he says, you can transfer skin cells and hair, which plays to some people's lower threshold for the gross, but won't result in infection, he says. (credit:Getty)
Nail Clippers, Buffers And Files(04 of10)
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You wouldn't share 'em at a salon -- so don't share them with pals, either. If cuticles are cut or pushed back too far, or callused skin is removed, you could have little cuts in your skin, perfect openings for bacteria, fungus, yeast and viruses to be exchanged from tools that haven't been properly sanitized between users, according to the Today Show. Hepatitis C, staph infections and warts can all be spread this way. (credit:<a href="http://www.flickr.com/" role="link" class=" js-entry-link cet-external-link" data-vars-item-name="Flickr" data-vars-item-type="text" data-vars-unit-name="5b9dea51e4b03a1dcc8ea172" data-vars-unit-type="buzz_body" data-vars-target-content-id="http://www.flickr.com/" data-vars-target-content-type="url" data-vars-type="web_external_link" data-vars-subunit-name="before_you_go_slideshow" data-vars-subunit-type="component" data-vars-position-in-subunit="13" data-vars-position-in-unit="18">Flickr</a>:<a href="http://www.flickr.com/photos/19457811@N00/281092754" role="link" class=" js-entry-link cet-external-link" data-vars-item-name="supermattzor" data-vars-item-type="text" data-vars-unit-name="5b9dea51e4b03a1dcc8ea172" data-vars-unit-type="buzz_body" data-vars-target-content-id="http://www.flickr.com/photos/19457811@N00/281092754" data-vars-target-content-type="url" data-vars-type="web_external_link" data-vars-subunit-name="before_you_go_slideshow" data-vars-subunit-type="component" data-vars-position-in-subunit="14" data-vars-position-in-unit="19">supermattzor</a>)
Makeup(05 of10)
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Keep your mascara wands and lipstick tubes to yourself if your friend who wants a swipe has an obvious infection, like pinkeye or a cold sore. But Schultz says that on a case-by-case basis, makeup may actually be safe to share. That's because most cosmetics have a number of preservatives on the labels, which are designed to kill bacteria and other growths in products made with water, thereby cutting down on infections. (credit:Getty)
Razors(06 of10)
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It probably goes without saying, but you should never share anything that could exchange blood. "Avoid sharing anything that might have contact with blood, even if there's no apparent blood," says Tosh.Since shaving can result in tiny nicks in the skin, viruses and bacteria left behind on razors can enter swiftly into the blood, according to "The Dr. Oz Show", and blood-transmitted viruses like hepatitis B are "unbelievably transmissible," says Tosh. (credit:AP)
Drinks(07 of10)
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Sharing a water bottle or a cup can lead to saliva swapping -- and not in a good way. The germs that cause strep throat, colds, herpes, mono, mumps and even meningitis can all be exchanged with a seemingly-harmless sip, dentist Thomas P. Connelly writes. However, Tosh points out that while many people carry the virus that causes cold sores, some won't ever actually have one. "Should you never share a soda?" he says, incredulously. "Usually, it's not going to cause problems." (credit:Getty Images)
Toothbrushes(08 of10)
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Sharing is a no-no, according to the CDC, since you could pass infections along on those bristles, especially if, say from flossing, there is any small amount of bleeding, says Schultz. (credit:<a href="http://www.flickr.com/" role="link" class=" js-entry-link cet-external-link" data-vars-item-name="Flickr" data-vars-item-type="text" data-vars-unit-name="5b9dea51e4b03a1dcc8ea172" data-vars-unit-type="buzz_body" data-vars-target-content-id="http://www.flickr.com/" data-vars-target-content-type="url" data-vars-type="web_external_link" data-vars-subunit-name="before_you_go_slideshow" data-vars-subunit-type="component" data-vars-position-in-subunit="6" data-vars-position-in-unit="11">Flickr</a>:<a href="http://www.flickr.com/photos/55252106@N00/9781548242" role="link" class=" js-entry-link cet-external-link" data-vars-item-name="lundyd" data-vars-item-type="text" data-vars-unit-name="5b9dea51e4b03a1dcc8ea172" data-vars-unit-type="buzz_body" data-vars-target-content-id="http://www.flickr.com/photos/55252106@N00/9781548242" data-vars-target-content-type="url" data-vars-type="web_external_link" data-vars-subunit-name="before_you_go_slideshow" data-vars-subunit-type="component" data-vars-position-in-subunit="7" data-vars-position-in-unit="12">lundyd</a>)
Earrings(09 of10)
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When you poke an earring through your ear, you may make a little break in the skin, allowing viruses from the last wearer to enter the blood, according to "The Dr. Oz Show". Tosh points out that most people inserting earrings won't be drawing blood, but there is still potential risk if you don't clean your jewelry between wearers. (credit:Getty)
Earphones(10 of10)
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We know you love your jams, but frequent earphone use seems to up the amount of bacteria in your ears, according to a 2008 study. That bacteria could spread to another's ear if you share headphones, and could lead to ear infections. Avoid sharing -- or at least wash 'em first -- which, by the way, you should probably do more frequently anyway! Even over-the-ear headphones could pass along lice, says Schultz (credit:<a href="http://www.flickr.com/" role="link" class=" js-entry-link cet-external-link" data-vars-item-name="Flickr" data-vars-item-type="text" data-vars-unit-name="5b9dea51e4b03a1dcc8ea172" data-vars-unit-type="buzz_body" data-vars-target-content-id="http://www.flickr.com/" data-vars-target-content-type="url" data-vars-type="web_external_link" data-vars-subunit-name="before_you_go_slideshow" data-vars-subunit-type="component" data-vars-position-in-subunit="2" data-vars-position-in-unit="7">Flickr</a>:<a href="http://www.flickr.com/photos/26037046@N00/4290196026" role="link" class=" js-entry-link cet-external-link" data-vars-item-name="Khairil Zhafri" data-vars-item-type="text" data-vars-unit-name="5b9dea51e4b03a1dcc8ea172" data-vars-unit-type="buzz_body" data-vars-target-content-id="http://www.flickr.com/photos/26037046@N00/4290196026" data-vars-target-content-type="url" data-vars-type="web_external_link" data-vars-subunit-name="before_you_go_slideshow" data-vars-subunit-type="component" data-vars-position-in-subunit="3" data-vars-position-in-unit="8">Khairil Zhafri</a>)

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