Table 1

Study characteristics

StudyLocationAge rangeInclusion and exclusion criteriaSample sizeRadiographic pneumonia,
N (%)
Definition of pneumonia by chest radiograph
Puumalainen et al and Arcay, et al. (ARIVAC)48 49Philippines6 weeks to 59 monthsTachypnoea*, lower chest indrawing (severe pneumonia)† or cyanosis and/or inability to drink (very severe pneumonia)‡1153187 (16.2)Primary end point pneumonia (PEP)§
Basnet et al50Nepal2–35 monthsCough <14 days and/or difficulty breathing ≤72 hours with presence of lower chest indrawing, provided lower chest indrawing persisted after 3 doses of bronchodilators.551135 (24.5)Lobar pneumonia/
Gentile et al51Argentina0–59 monthsChildren hospitalised with pneumonia.401201 (50.1)PEP§
Gessner et al52Indonesia0–24 monthsWHO defined non-severe** and severe pneumonia†.58141025 (17.6)PEP§
Hortal et al53Uruguay0–59 monthsChildren hospitalised with acute lower respiratory tract infection with chest X-ray performed.811412 (50.8)PEP§
Tan et al54Indonesia<5 yearsAll children with diagnosis of pneumonia and having >1 of the following: fever, cough, dyspnoea, or tachypnoea*.1251128 (10.2)Lobar pneumonia/
Neuman, et al24USA0–59 monthsChildren with chest X-ray performed for suspicion of pneumonia. Excluded children with chronic conditions.1796161 (9.0)PEP§
O'Grady et al55Central Australia0–59 monthsChild with cough with tachypnoea* and/or chest indrawing†. Excluded children with wheezing and chronic conditions.14740 (27.2)PEP§
Ferrero et al56Argentina1–59 monthsWHO defined non-severe** and severe pneumonia†. Excluded hospital-acquired pneumonia.20851123 (53.9)PEP§
Turner et al57Thailand0–2 yearsWHO defined non-severe** and severe pneumonia†.1020331 (32.5)PEP§
  • *Tachypnoea: respiratory rate ≥60 per minute in infants <2 months old, ≥50 per minute in infants 2–11 months old, or ≥40 per minute in children 12–59 months of age.

  • †Severe pneumonia (old WHO pneumonia classification): cough and/or fast breathing with lower chest indrawing.

  • ‡Very severe pneumonia (old WHO pneumonia classification): one or more danger sign including abnormally sleepy, lethargy, central cyanosis, inability to drink, convulsions, head nodding/bobbing, nasal flaring or grunting.

  • §PEP: a dense opacity that may be a fluffy consolidation of a portion or whole of a lobe or of the entire lung, often containing air bronchograms and sometimes associated with pleural effusion.

  • ¶Lobar pneumonia or consolidation: Chest X-ray findings showing lobar pneumonia or consolidation.

  • **Non-severe pneumonia: cough and fast breathing, defined as respiratory rate of >50 per minute in children 2–11 months old or >40 per minute in children 12–59 months old.