Table 1 Study definitions

World Health Organization (WHO) Integrated Management of Childhood Illness (IMCI) general danger signs

Lethargy or unconsciousness, convulsions, vomiting everything, or inability to drink or breastfeed

Respiratory danger signs

Grunting, nasal flaring, head nodding, severe chest indrawing, or hypoxemia (pulse oximetry saturation < 90%)

Fast-breathing pneumonia

History of cough < 14 days or difficult breathing with fast breathing-for-age (> 50 breaths/minute in children 2 to < 12 months of age, >  40 breaths/minute in children > 12 months of age) in the absence of chest indrawing and WHO IMCI general and respiratory danger signs

Chest-indrawing pneumonia

History of cough < 14 days or difficult breathing with chest indrawing in the absence of WHO IMCI general and respiratory danger signs

Danger sign pneumonia

History of cough < 14 days or difficult breathing and the presence of WHO IMCI general and/or respiratory danger signs

Chest radiograph (CXR)-confirmed pneumonia

History of cough < 14 days or difficulty breathing with CXR features of pneumonia per the assessment of the clinician interpreting the CXR in the absence of fast breathing-for-age, chest indrawing, and WHO general and respiratory danger signs

First-line intravenous antibiotic treatment failure

Persistence or presence of new WHO general or respiratory danger signs after at least 2 days of receiving intravenous benzyl penicillin and gentamicin

Second-line intravenous antibiotic treatment failure

Persistence or presence of new WHO general or respiratory danger signs after at least 5 days of receiving intravenous ceftriaxone