Pneumonia is an infection or inflammation (swelling) of the lungs caused by a germ. When you have pneumonia air sacs in the lungs fill with liquid and cannot function properly. It is spread from person-to-person in the air. Signs can be fever, chills, headache, ear pain, cough, chest pain, confusion and shortness of breath. Quickly seek treatment from a hospital if you suspect pneumonia. Best prevention is vaccination but not all types of pneumonia can be vaccinated against.
Attribution: Straight Talk Foundation & Marie Stopes