The picture above is from a standard Colgate toothbrush from a standard Manhattan drug store. The warning it comes with passes along standard advice: if you catch a cold, change your toothbrush after you recover. After all, you don’t want to re-infect yourself.
That advice is almost certainly wrong. For a few reasons, in fact.
When your body finally fights off that could which has been dogging you for the better part of a week, you’ve done more than simply recover. As Slatenotes, “[o]nce you’ve been infected with a particular strain of a virus, you develop antibodies that make the likelihood of re-infection very low” — so you probably are almost immune from your own germs. And even if you did not, many viruses simply don’t last that long on your bristles (although the flu can hang out there, ready to infect someone else, for three or four days). While other illnesses are caused by bacteria, there is little reason to worry about that, either, as many toothpastes contain antibacterial goodness ready to go to battle before the bristles hit your teeth.
The American Dental Association has an advice punchlist which includes tips for good toothbrush care, but again, throwing yours away after battling a cold is simply not there. Most likely, the “advice” is marketing claptrap. What does make the list? Replace your toothbrush when bristles wear out (every 3-4 months, roughly); do not keep your toothbrush in an enclosed container, as to avoid growing microorganisms on it; rinse your brush well after use; and of course, do not share toothbrushes.
Bonus fact: Another reason to not share toothbrushes? Cavities. It turns out, cavities may be contagious.
From the Archives: Pumpkin Saving Time: How candy led to an extra hour of daylight.