Participants
Women were recruited from the Mombasa Cohort, a long-term open cohort study of FSW in Mombasa, Kenya [After nine months, due to slow enrollment, the inclusion criteria were expanded to include women who did not engage in sex work. This change was possible because the messages focused on information, motivation, and behavioral skills for ART adherence, and were not specific to the context of transactional sex. General population women were recruited from voluntary counselling and testing centers and met all other eligibility criteria.