Identifying networks of young men and mapping their social venues for a cluster randomized trial in Dar es Salaam, Tanzania

HIV/AIDS disproportionally affects youth in sub-Saharan Africa. Identifying venues to access male social networks, especially in urban settings where HIV prevalence is often highest and men are not being reached, is a challenge. Camps, the U.S. equivalent of a club or support group, were previously identified as potential venues to access men.  In randomized controlled trials with venues as the sampling unit, minimizing contamination across venues is a challenge.

We are conducting an RCT with camps as the sampling unit within four wards of Dar es Salaam, Tanzania.  We conducted 489 community informant interviews to identify camps and 619 verification interviews to characterize these camps. Camps were mapped with GIS software. 

A total of 303 camps were verified. Camps had an average of 26 male members and 90% had some female members. Almost all camps (99%) existed over a year, and 87% existed more than 3 years.  Nearly all (91%) are accessible throughout the year and 60% are located on a main road. We used GIS mapped coordinates to group geographically contiguous camps into 93 clusters prior to random selection of 60 study camps. In the event multiple camps from the same cluster were selected for inclusion in the trial, these camps were assigned to the same condition to minimize contamination.

Camps are venues where we can reach stable networks of young men for health promotion activities.  GIS mapping helped identify contiguous camps, which allowed us to minimize contamination during the random selection of camps for this cluster randomized trial.