Pneumonia is a lung infection involving the lung alveoli (air sacs) and can be
caused by microbes, including bacteria, viruses, or fungi. It is the leading infectious
cause of hospitalization and death in the United States and exacts an enormous
cost in economic and human terms. Healthy individuals can develop pneumonia,
but susceptibility is greatly increased by a variety of personal characteristics.
Whom does it affect?
Epidemiology, prevalence, economic burden, vulnerable populations
Pneumonia was described 2,500 years ago by Hippocrates, the father of medicine.
Dr. William Osler, the founder of modern medicine, who studied pneumonia
throughout his career, called pneumonia the “captain of the men of death”
because of the great toll it exacted on humanity. Pneumonia occurs commonly
in individuals living in their home communities (“community-acquired pneumonia”)
as well as in individuals who are hospitalized for other reasons (“hospitalacquired
pneumonia”). In the 1930s, before the advent of antibiotics, pneumonia
was the third-leading cause of death in the United States. Notably, it remains
a leading cause of death. In 2006, it was the eighth-leading cause of death,