Pneumonia is an infection that inflames the air sacs in one or both lungs. The air sacs may fill with fluid or pus, causing symptoms such as cough with phlegm or pus, fever, chills, and difficulty breathing. Pneumonia can range in severity from mild to life-threatening and is most commonly caused by bacteria or viruses.

Pneumonia is a significant global health concern, especially among young children, older adults, and individuals with weakened immune systems. Prompt medical attention and appropriate treatment are essential for reducing complications and improving outcomes in cases of pneumonia.