Reaching the unreachable: providing STI control services to female sex workers via mobile team outreach

Abstract

Background: As part of a community-randomized trial of a multicomponent intervention to prevent sexually transmitted infections, we created Mobile Teams (MTs) in ten intervention cities across Peru to improve outreach to female sex workers (FSW) for strengthened STI prevention services.

Methods: Throughout 20 two-month cycles, MTs provided counseling; condoms; screening and specific treatment for Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), and vaginal Trichomonas vaginalis (TV) infections; and periodic presumptive metronidazole treatment for vaginal infections.

Results: MTs had 48,207 separate encounters with 24,814 FSW; numbers of sex work venues and of FSW reached increased steadily over several cycles. Approximately 50% of FSW reached per cycle were new. Reported condom use with last client increased from 73% to 93%. Presumptive metronidazole treatment was accepted 83% of times offered. Over 38 months, CT prevalence declined from 15.4% to 8.2%, and TV prevalence from 7.3% to 2.6%. Among participants in ≥ 9 cycles, CT prevalence decreased from 12.9% to 6.0% (p <0.001); TV from 4.6% to 1.5% (p <0.001); and NG from 0.8% to 0.4% (p = 0.07).

Conclusions: Mobile outreach to FSW reached many FSW not utilizing government clinics. Self-reported condom use substantially increased; CT and TV prevalences declined significantly. The community-randomized trial, reported separately, demonstrated significantly greater reductions in composite prevalence of CT, NG, TV, or high-titer syphilis serology in FSW in these ten intervention cities than in ten matched control cities.

Figure 1. Numbers of female sex workers and commercial sex venues reached by Mobile Teams.

The numbers of female sex workers and the numbers of commercial sex venues reached by mobile teams during the 20 eight-week intervention cycles is represented here. The numbers of sex work venues reached per cycle increased steadily from the first intervention cycle to the fifth cycle, then leveled off. Data from cycles 15 and 20 can’t be disaggregated from data for the 2005 and 2006 surveys of random samples of FSW in the ten cities, and therefore are not presented here.

Figure 2. Proportion of female sex workers new to Mobile Teams at each intervention cycle.

For each cycle, the number of encounters decreases from top to bottom of the figure; participants with greatest number of Mobile Team encounters are depicted at the top, those with lowest (i.e., new participants) at the bottom.

Figure 3. Prevalences of C. trachomatis and T. vaginalis infections among female sex workers.

The 95% confidence intervals are shown for Cycle 1 (when the number of encounters was smallest). Reductions in prevalences are significant for C. trachomatis (p <0·001) and for T. vaginalis (p <0·001).

Figure 4. Prevalences of C. trachomatis, N. gonorrhoeae, and T. vaginalis among sex workers.

The prevalences are presented in relation to the number of encounters with the Mobile Team. Analysis is restricted to 714 sex workers with at least nine encounters with the Mobile Team. 95% confidence intervals are shown for the first encounter. Reductions in prevalences are significant for C. trachomatis (p <0·001) and T. vaginalis (p <0·001), but not for N. gonorrhoeae (p =0·07). N. gonorrhoeae infection was defined by AMPLICOR NG OD ≥3·5, confirmed by positive Aptima Combo2 assay.