The incubation period is defined as the time interval between exposure to a contagious disease and the onset of symptoms. The contagious period is defined as that time interval during which a sick child's disease is contagious to others. Most physicians would agree that a child should stay home at least until he feels well enough to return to school, and the fever has been gone for 12 hours. Try not to become preoccupied with infections. Some of the more serious ones are not even contagious.
Some infections are due to blockage of a passageway followed by an overgrowth of bacteria.
Examples of these are ear infections, sinus infections, and urinary tract infections. Lymph node and bloodstream infections are also rarely contagious. Pneumonia is a complication of a viral respiratory infection in most cases and is usually not contagious. While exposure to meningitis requires consultation with your child's physician, most children exposed to this disease do not become infected. However, if the sores are on a part of the body that can be covered, your child does not need to stay home.