2.1. Study setting and sample

Data are from the baseline year of a longitudinal cohort study of population mobility embedded within the Sustainable East Africa Research in Community Health (SEARCH) trial (NCT# 01864603) [17]. As described elsewhere [16], the Mobility in SEARCH study (R01MH104132) was conducted in 12 SEARCH communities. We enrolled 2750 adults aged 15+ (consent rate of 98.3%), of whom 1440 were sexually active women (reporting any sexual partnerships in past six months) between 15–49 years. We used a multilevel stratified random sampling design (region, HIV status, mobility status, gender) to select individuals from the census-enumerated adult population of each of the communities. The 12 communities were composed of three communities each from two regions of Uganda, along with three inland, and three Lake Victoria shoreline communities in Kenya. For sampling purposes, we defined categories of baseline mobility status on the basis of SEARCH trial data on household presence in the past 12 months (mobile = “away from household 6 months or more in past 12 months”, and/or “fewer than half of nights spent in household in past 4 months”). Persons living with HIV and mobile individuals were oversampled to achieve the desired sample size in each stratum.