Intra-household pneumococcal transmission (multilevel logistic regression.

a Exposure defined as carriage of the target serotype in at least one household member in the specified age range at the previous visit. b Both child recipient and adult recipient models adjusted for seasonality (using the first two pairs of a truncated Fourier series), recipient characteristics (age, sex) and household characteristics (number of children <6 y, wood- or coal-burning indoor stove, and running water). Child recipient models also adjusted for vaccination status (defined as at least 3 doses of PCV7), and breastfeeding status (since last visit). Low PS23 coverage in adult age groups and the rarity of serotype-specific adult-to-adult exposure precluded the addition of PS23 vaccination status and exposure to carriage in adults ≥17 years to the adult model. Visits in which adults 17 years were exposed to carriage in another adult ≥17 years at the previous visit were excluded from the adult model.