Fig. 1.

Recruitment of men who have sex with men in Nairobi (N = 569 including seeds). Recruitment was initiated by six seeds who issued 1478 coupons, 691 were returned and out of these 563 met eligibility criteria for study participation and were enrolled in the study. The waves of recruitment per seed ranged from 1 to 23, and the mean network size was 77, while the median was 8 (IQR: 4, 20). Larger circles indicate seed participants