Individual-based and neighbourhood-based socio-economic factors relevant for contact behaviour and epidemic control

Identifying sources of heterogeneity in contact patterns is key to inform disease transmission models. Recent works have investigated how individual-based socio-economic factors, besides age, affect contact behaviour, but neglected the individuals’ area of living. Here, we aimed at estimating contact matrices stratified by both individual-based and area-based socio-economic factors. We used social contact data from Switzerland collected in 2021, combined with a neighbourhood-based index of socio-economic position (SEP). First, we found a positive association between education level and number of contacts in the elderly, and, notably, a negative association between SEP level and number of contacts in adults. Second, despite lacking socio-economic information on the contacts, we developed a method to reconstruct contact matrices fully stratified by age, education level, and SEP, with varying assortativity levels. Third, integrating the matrices into a transmission model revealed heterogeneous disease burden, with higher attack rates in adults with higher education level living in low SEP areas and seniors with higher education level living in high SEP areas. Adults and young individuals living in high SEP areas were the main contributors to transmission. We found that the less assortative contacts are, the higher the chances of a targeted strategy to be successful, and the lower the control effort required to prevent disease spread. Our results shed light on contact behaviour in previously neglected socio-economic groups, enable model integration of socio-economic indicators, and provide insights to improve disease control.