Essential facts: An infection of the lung tissue, pneumonia is common and has a high mortality rate. According to the National Institute for Health and Care Excellence (NICE), between 0.5% and 1% of adults will develop community-acquired pneumonia (CAP) every year. It is diagnosed in 5-12% of those who present to GPs with lower respiratory tract infection, with 22% to 42% admitted to hospital, where the mortality rate is between 5% and 14%. Hospital-acquired pneumonia is estimated to increase hospital stay by about eight days, and has a reported mortality rate ranging from 30% to 70%.