Short answers, pulled from the story.
Pneumonia is an inflammatory condition of the lung that primarily affects the small air sacs known as alveoli. Symptoms typically include a productive or dry cough, chest pain, fever, and difficulty breathing, and the severity varies.
Pneumonia is usually caused by infection with viruses or bacteria, and less commonly by fungi and parasites. Streptococcus pneumoniae is the most common bacterial cause, isolated in nearly 50 percent of community-acquired cases, while in adults viruses account for about a third of cases.
Pneumonia affects about 450 million people globally each year, roughly 7 percent of the population, and results in about 4 million deaths. Rates are greatest in children under five and adults older than 75, and it occurs about five times more often in the developing world than the developed world.
Pneumonia is typically diagnosed through a combination of physical signs and often a chest X-ray, with lung ultrasonography gaining prominence as an accurate alternative. There is no definitive test to distinguish bacterial from non-bacterial causes, and the causative agent is identified in only about 15 percent of cases with routine tests.
Pneumonia thought to be bacterial is treated with antibiotics, and for many people oral antibiotics, rest, simple painkillers, and fluids are enough. In the UK amoxicillin is recommended first for community-acquired pneumonia, severe cases are generally hospitalized, and oxygen therapy may be used when oxygen levels are low.
Vaccines are available against certain types of pneumonia, including those caused by Streptococcus pneumoniae, influenza viruses, and SARS-CoV-2. The pneumococcal vaccine lowers the risk of invasive pneumococcal disease by 74 percent, and in October 2024 the CDC lowered the recommended age for adult pneumococcal vaccination from 65 to 50.
Pneumonia has been called "the old man's friend" because it often shortens the period of suffering among those already close to death, with a quick and relatively painless ending. Sir William Osler used the phrase, and also called pneumonia "the captain of the men of death" in 1918.