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I was in a supermarket yesterday and saw the following on a toothbrush:

"Got a cold? Change your toothbrush." sticker on toothbrush package

I found the advice repeated on the Colgate website:

It is also very important to change toothbrushes after you've had a cold, since the bristles can collect germs that can lead to reinfection.

Can you be reinfected by your own toothbrush if you've had a cold?

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This depends on what you were sick with, and how long the toothbrush was not used since you last had the sickness.

  • You CAN get reinfected with a bacterial infection (e.g. strep throat) from a toothbrush

    http://www.nlm.nih.gov/medlineplus/ency/article/000639.htm

    Most people with strep are contagious until they have been on antibiotics 24 - 48 hours. They should stay home from school, daycare, or work until they have been on antibiotics for at least a day.

    Get a new toothbrush after you are no longer contagious, but before finishing the antibiotics. Otherwise the bacteria can live in the toothbrush and re-infect you when the antibiotics are done. Also, keep your family's toothbrushes and utensils separate, unless they have been washed.

  • Viruses can also be retained on toothbrushes, with research showing minutes to 24 hours to 48 hours depending on the virus. Example:

    http://www.ncbi.nlm.nih.gov/pubmed/7931767

    "The effectiveness of a u-v toothbrush sanitizing device in reducing the number of bacteria, yeasts and viruses on toothbrushes." Glass RT, Jensen HG.- Department of Oral Pathology, University of Oklahoma College of Dentistry

    Seventy-two sterile toothbrushes were exposed to Herpes Simplex Virus, Type I and seventy-two sterile toothbrushes were exposed to Parainfluenza Virus, Type III. The Pollenex DS60 Daily Dental Sanitizer consistently killed both viruses on all of the toothbrushes treated. Both viruses were consistently retained on non-treated toothbrushes for at least 24 hours.

    However, in case of common cold virus, the reinfection risk is presumably reduced by the fact that you have already developed immunity to the strain you had.

  • 3
    Good answer, but could you give some more details on your last point about cold virus immunity? – Tom77 Nov 25 '11 at 12:52
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    @Tom77 - the fact that you have recovered from cold means that your immune system developed enough antibodies that you now have resistance to that particular strain. And the virus on a toothbrush won't be replicating and mutating. – user5341 Nov 25 '11 at 19:34
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    Other question: does it hurt to get reinfected? Your specific immune system is up and running, and butchers anything that comes in via the toothbrush. This is even more true if you haven’t taken antibiotics. – Konrad Rudolph Nov 26 '11 at 21:07
  • Could it help to put the toothbrush in boiling water? Do the viruses survive, even if the toothbrush dries completely? – user unknown Jan 18 '12 at 12:18

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