Recruitment of Participants
RECRUITMENT
In August 2017, we invited the 651 FSWs from a cohort created in 2015 to attend a survey interview at a health facility. Inclusion criteria required participants to be active FSWs and to be over 21 years old. Note that this sample was stratified by the registration status of the FSWs and as a result included an equal proportion of registered and unregistered sex workers. Registered FSWs were recruited by midwives based on their hospital file from four (out of five) STI centers located in suburbs of the capital Dakar (Rufisque, Pikine, Mbao, and Sebikotane).Non-registered FSWs were recruited by non-registered peer leaders. Out of the 651 FSWs, 441 agreed to participate, and the cohort was replenished with an additional 150 FSWs using the same method of recruitment as for the initial cohort. As a result, 591 participated in the study. However, 28 were excluded from the analysis due to inconsistencies in their responses and understanding of the probability questions; 563 participants were included in the final analysis.Interviews were conducted in separate rooms by professional interviewers. Ethical clearance was obtained from a higher education institution in the UK and from the national ethics committee in Senegal. Written consent was collected from participants in order for them to participate in the study. Data were stored on a secured server, and anonymized data were used for data analysis.