Respiratory Tract Infections (RTIs) are the most common health problem in childhood, with children suffering on average 4-8 RTIs a year. Social determinants like parental education and household income, in addition to environmental and behavioural risk factors early in life, can influence susceptibility to RTI outcomes. Children living in disadvantaged socio-economic circumstances (SECs) are more likely to suffer from severe RTI outcomes, but the pathways leading to these inequalities are complex, inter-related and poorly understood. The overall objective of this project is to understand the burden of Upper and Lower Respiratory Tract Infections in children in Europe. Using federated analyses of data from the EU Child Cohort Network, the project aims to explore the social and geographic patterns and the pathways that relate social characteristics, early-life risk factors and childhood RTIs. Understanding these patterns and pathways is vital to inform preventative policy and help reduce the unfair child health differences through effective public health interventions.