Household‐level risk factors for influenza among young children in Dhaka, Bangladesh: a case–control study

OBJECTIVES: To identify household-level factors associated with influenza among young children in a crowded community in Dhaka, Bangladesh. METHODS: We conducted a case-control study using existing active surveillance for respiratory illness. Cases were children aged 12-59 months with laboratory-confirmed influenza. Controls were children frequency-matched by age group with no respiratory illness in the prior 6 months. We interviewed caregivers and observed household handwashing behaviour. Soap consumption was estimated by summing weight differences of three bars of soap sequentially left in each household. We measured concentrations of airborne particulate matter <2.5 μg in diameter (PM2.5) in a subset of households. We used logistic regression to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI). RESULTS: We enrolled 145 cases and…