The impact of time at home on potential yield of home-based TB contact investigation

BACKGROUND: The yield of TB contact tracing is often limited by challenges in reaching individuals during the screening process. We investigated the times at which index patients and household contacts were typically at home and the potential effects of expanding the timing of home-based contact investigation. METHODS: Index patients and household contacts in Kampala, Uganda, were asked about their likely availability at different day/time combinations. We calculated the "participant identification gap'' (defined as the proportion of participants who reported being home >50% of the time) during business hours only. We then estimated the incremental reduction in the participant identification gap if hours were expanded to include weekday evenings, Saturdays, and Sundays. Statistical significance was assessed using McNemar's tests. RESULTS : Nearly half of eligible individuals (42% of index patients and 52% of contacts) were not likely to be home during contact investigation conducted only during business hours. Expanding to weekday evenings, Saturdays, and Sundays would reduce this participant identification gap to 15% among index patients and 18% among contacts - while also reducing differences by sex and employment. CONCLUSIONS : Expanding hours for conducting contact investigation or other home-based health interventions could substantially reduce the number of individuals missed and address disparities in access to care.