“…Of the 88 studies, 14 were in East Asia (all of which were from China)[12], [13], [28]–[39], 16 in South Asia [3], [16], [17], [40]–[52], 15 in Southeast Asia [7], [9], [15], [53]–[64], 11 in Latin America [2], [14], [18], [65]–[72], 9 in Sub-Saharan Africa [73]–[81], 9 in Europe [8], [10], [82]–[88], and 14 in North America [1], [5], [89]–[99]. Of these, 66 [1]–[3], [7]–[9], [12], [14]–[17], [28], [29], [31]–[39], [41]–[51], [53], [55], [57], [59]–[61], [63]–[67], [70]–[72], [74]–[77], [79]–[88], [93]–[95], [100] included a biological HIV assay and had a sample size of ≥50, and thus were included in the analyses, representing 31,924 men who engaged in transactional sex with other men in 28 countries (Figure 1). …”