20 Myths and facts about cold and flu

If you don't have a fever, you're not contagious

Why it's not true: If you have a cold, you're most contagious for the first 2 to 3 days, whether you have a fever or not, according to the National Institutes of Health. "Sometimes, at our house, the fever is 'the Grand Finale' of everyone's cold—it shows up at the very end," says Mary Linda Swiatek, mother of two children, ages 14 and 12, in Lake Mary, Florida. Swiatek says she has long been aware that contagiousness can precede visible symptoms. The contagious phase of a cold virus is usually over by day 7 to 10. Adults and older children with colds generally have a low fever or no fever. Young children, though, often run a fever around 100° to 102°F.