Pneumonia refers to various lower respiratory problems that involve swelling of the small air passages in the lungs (alveoli). Pneumonia in children occurs most often in infancy and early childhood. It can be caused by viruses, bacteria, or an object lodged in an air passage. Pneumonia may vary from mild to life-threatening. Bacterial pneumonia can be a serious illness.

The symptoms of pneumonia may be mild or severe and can include:

• Fever.
• Cough.
• Shortness of breath.
• Difficulty breathing.
• Rapid breathing.
• Fatigue ranging from mild tiredness (malaise) to exhaustion.
• Irritability, restlessness, poor appetite, and decreased activity level.

Chlamydia is a sexually transmitted infection that can cause a life-threatening pneumonia in newborns. A baby may get pneumonia during birth by inhaling some of the bacteria from the birth canal. The symptoms of chlamydia pneumonia are a persistent cough, rapid breathing, and mild or no fever.