Pneumonia cases were hospitalized children who fulfilled the following criteria:
- Cough and/or dyspnea, and
- Tachypnea, as characterized by the World Health Organization (WHO) in children between 2 and 12 months of age: breathing rate ≥50 cycles per minute; in children between 12 and 59 months of age: breathing rate ≥40 cycles per minute) [13], and
- Absence of wheezing at auscultation, and
- First symptoms appearing within the last 14 days, and
- Radiological confirmation of pneumonia as per WHO guidelines