Fig. 1

Schematic representation of the study participants and LRTI episodes detected in the birth cohort in Biliran, Philippines, from March 2014 to June 2016. ^aRespiratory symptoms included cough, difficulty breathing or coryza. ^bDiagnosis of severe pneumonia was based on the criteria of the Integrated Management of Childhood Illness (IMCI). Ten LRTI episodes were classified as undefined LRTI because SpO₂ data were missing (n = 2) or it was not possible to assess as its measurement was performed after starting oxygen treatment (n = 8). Abbreviation: LRTI, lower respiratory tract infection; SpO₂, percutaneous oxygen saturation. Almost all children in the study area were participated the study, though approximately 10 children refused to participate. Within 419 children, 183 children were followed until 1 year of age and 64 children were followed until 2 years of age, whereas 84 children were not followed until 6 months of age