Pneumonia is a type of respiratory infection. It can occur in one or both lungs. One-third of pneumonia cases in the United States are caused by respiratory viruses. Of these, the flu virus is the most frequent cause of adult viral pneumonia.
Although colds do not turn into pneumonia, they do increase the chances of developing it. A cold is one of the most common risk factors for pneumonia. Other risk factors include smoking, chronic lung disease, cerebral palsy, a weakened immune system, recent physical trauma or surgery.Learn more about Conditions & Diseases