Table 1.

Detailed description of study methods.

Study population (recruitment dates)			Detailed sampling methodsa	Eligibility criteriab
Respondent-driven samplingc			Seeds were recruited from local MSM- or FSW-affiliated communicated-based organizations (although not all seeds were members. Each participant was given three coupons to distribute. Sample size calculations for the initial data collection were powered based on the ability to estimate local HIV prevalence of MSM and FSW, and the required sample sizes were achieved.	Possess valid recruitment coupon
	Swazilandd (July - December 2011)
		MSM	4 of 5 seeds successfully accrued 326 men through up to 14 waves. A few participants (n=16) could not be traded back to valid sees and were excluded post-hoc.	Report receptive or insertive anal sex with another man for the last 12 months
		FSW	10 of 14 seeds successfully recruited 325 FSW through up to 7 waves	Report exchanging sex for money, favors, or goods in last 12 months
	Cameroone
		MSM (November 2015 - January 2016)	2 of 4 MSM seeds successfully accrued 306 men through up to 12 waves	Report receptive or insertive anal sex with another man for the last 12 months
		FSW (December 2015 - February 2016)	2 of 3 seeds successfully recruited 576 FSW through up to 22 waves	Report more than half income in the past 12 months from sex work
Snowball sampling			Participants were recruited through snowball sampling at “hotspot” venues. MSM and FSW venues were visited by study staff, and participants were approached at each of the venues to provide informed written consent and completed the interviewer-administered survey. In many locations, venue managers or key community leaders acted as key informants and assisted staff in identifying MSM and FSW and facilitating introductions.
	Swazilandd (October - November 2014)		A modified version of the PLACE method [43] was used to characterized venues where MSM and FSW meet new potential sexual partners.
		MSM	173 MSM were recruited. 7 unique venues in Manzini/Matsapha were mapped and 2 were sampled from.	Report receptive or insertive anal sex with another man for the last 12 months
		FSW	249 FSW were recruited. 12 venues were mapped and 2 were sampled from.	Report exchanging sex for money, favors, or goods in last 12 months
	Cameroone(April - May 2013)
		MSM	259 MSM were recruited. 4 unique venues were mapped and 3 were sampled from.	Report receptive or insertive anal sex with another man for the last 12 months
		FSW	308 FSW were recruited. 15 venues were both mapped and sampled from.	Report more than half income in the past 12 months from sex work

^aAll surveys were conducted using face-to-face interviews in private locations.

^bAll participants had to be at least 18 years of age.

^cRecruiters were additionally compensated the equivalent of up to US $2 for each participant they recruited into the study.

^dParticipants were reimbursed for their time and travel to the study site dependent on distance traveled to and from the study site.

^eParticipants were reimbursed for the average cost of a meal and transportation (~US $5).