Pneumonia can be caused by viruses, bacteria, or fungi. Some common ones are:
- Streptococcus pneumoniae: The main cause of bacterial pneumonia in kids.
- Haemophilus influenzae type b (Hib): The second most common bacterial cause.
- Respiratory syncytial virus: The leading viral cause of pneumonia.
- Pneumocystis jiroveci: A common cause in HIV-infected infants.