Pneumonia is a type of lung infection, usually with a viral or bacterial cause, but also occasionally triggered by fungi or parasites. Symptoms of pneumonia include intense chest pain, fever, a productive cough and breathing problems. Vaccines and antibiotics have made pneumonia far less deadly than it was in the past, but it can still cause serious complications or even death, especially in elderly patients and in people with compromised immune systems. Viral and bacterial cases of pneumonia are contagious, so sequestering of an acutely ill patient may be necessary to prevent the spread of the disease.