Age. Based on 6 studies, the age-specific incidence of pneumonia in children ,1 year of age ranged from 0.01±0.68 episodes per person-year using either clinical or WHO case definitions [16, 17, 18, 19, 24, 25] . Based on 9 studies of children ,5 years, the incidence ranged from 0.06±0.27 episodes per personyear using clinical case definition and from 0.14±0.66 using the WHO case definition (Table S2) [16, 18, 19, 21, 24, 25, 26, 27, 28] . Incidence was lower in older children [16, 25] , and one study presented a pneumonia incidence for adults: 0.037 episodes per person-year for people $65 years of age [20] .