To avoid re-infecting yourself DURING and after a cold/flu, soak your toothbrush in rubbing alcohol to kill the germs.
Cold / Flu Re-Infection
Toothbrushes can re-infect people with the same cold/flu they have just gotten over. Wash toothbrushes in the dishwasher after being sick.
Cold / Flu Prevention
To prevent colds and flu, parents and kids should not share tubes of toothpaste. Each family member should have their own tube of toothpaste.