Although colds are a minor health problem, in the United States they account for more visits to the doctor than any other condition. Colds are caused by many different viruses, and until recently it was thought that a single vaccine could not be developed for all or most of them. However, new research approaches may make such a vaccine possible. Adults have an average of two to four colds a year, mostly between September and May. Summer colds are relatively rare. Young children suffer from an average of six to eight colds a year.
Colds are highly contagious.
They spread when droplets of fluid that contain a cold virus are released into the air and someone breathes them in, or when these droplets are transferred by touch. If you don't bundle up when outdoors in cold weather, you'll catch cold. Symptoms Between one and three days after a cold virus enters the body, cold symptoms start developing. Some people get a slight fever, and infants and young children are more likely to develop a higher temperature. Smokers usually have more severe symptoms than people who don't smoke.