This study adds evidence of considerable burden of infection with some but not all GTIs and HIV among a subpopulation of Peruvian FSWs.
There are several limitations to our study; principally that interpretation is based on cross-sectional data which precludes evaluation of the temporal relationship between risk factors and GTIs. The statistical power to understand relationships with some correlates, particularly for HSV-2, was limited as the sample size was small. Participants were asked sensitive questions regarding their behaviors and thus their responses may have been affected by recall and social desirability biases. Because we followed international standards for framing these questions and used rigorously trained interviewers, we believe these effects were minimized. The generalizability of study results to other clandestine FSWs is likely limited due to the snowball sampling methods and recruitment efforts which favored the adjacent neighborhoods of Lima Cercado (downtown Lima) and La Victoria. Participation bias may also have occurred if recruitment efforts predominantly captured women with existing conditions or pressing health concerns.
Our data revealed that the HIV seroprevalence of 2.4% in this study was lower than two historical estimates: one study reported a 9.6% seroprevalence among 146 clandestine FSWs, compared to an estimate of 0.3% among 5,827 registered FSWs [18
]; in a second unpublished study researchers found a 5% seroprevalence of 311 clandestine sex workers in Lima, Peru [4
]. Our data highlight effective efforts by the Peruvian public health community to stave off widespread HIV transmission in this vulnerable population. Nonetheless, despite nearly universal condom use with clients, FSWs had an elevated risk of HIV infection in comparison to the general population of women who reported HIV seroprevalence consistently well below 1% for the same time period [19
This study also documents prevalence rates of concern for other GTIs. Participants had an HSV-2 seroprevalence rate of 80% which is similar to an estimate from a 1992 Peruvian study of registered and unregistered FSWs [20
], but much higher compared to a 2002 estimate of 20% among women in the general population reported in a study of three Peruvian coastal cities [21
]. Bivariate analyses reported here show increasing risk of infection at older ages. No association with condom use was detected, consistent with the assessment that condom use is less effective against HSV-2 acquisition compared to other STIs [22
]. Evidently previous public health interventions were unsuccessful at preventing the steady accumulation of HSV-2 infections among FSWs. Over the past 10 years there have been no HSV-2-related public health interventions for FSWs. Furthermore, the BV prevalence of 44.8% identified here is the highest estimate reported to date in Peru and considerably higher than a comparable estimate of 20% among FSWs [23
], yet similar to the range of estimates reported for Central American FSWs [24
]. In our study women with BV were more likely to be diagnosed with another GTI, and BV diagnosis was independently associated with lack of condom use, associations which are consistent with other studies [25
Our estimate of 9% syphilis seroprevalence is comparable with an 11% estimate from the mid-1990s [4
], but higher than the 3.3% reported earlier that decade [2
] and 4.1% identified among primarily registered sex workers [30
]. Our study reports no evidence of recent syphilis, consistent with an interpretation of low frequency of transmission. The prevalence rate of 2% for T
was lower than 4.1% among 916 FWS reported previously [30
Our results suggest areas where efforts to build knowledge and awareness and to elicit sustained behavior change could further benefit sexual and reproductive health in this marginalized population. The high percentage of women who reported experiencing vaginal discharge or a genital ulcer in the past year likely does not capture the full range of GTI-related morbidity in this population as familiarity with the range of associated symptoms was low. A minority of FSWs recognized genital ulcers and malodorous vaginal discharge () as GTI symptoms despite high prevalences of HSV-2 and BV. Moreover, nearly three-quarters of the women did not seek medical care as their first response to vaginal symptoms whereas pharmacies were the preferred source for medical attention suggesting that self-medication and alternatives to specialized GTI services appear to be the preferred recourse. An underutilization of appropriate clinical services and an overreliance on informal sources of health care were further evidenced by findings indicating that 38% of participants with a history of vaginal symptoms reported never having visited an STI clinic or no visits in the past year; 27% had never tested for HIV and an additional 28% had not tested in the past year. Stigma, driven by discriminatory treatment and concerns for confidentiality, is a major reason for reluctance to use free STI clinic services [31
]. Some in the Peruvian context have worked towards strengthening the capacity for pharmacies to provide information and medication based on syndromic STI case management approaches [32
]; however the effectiveness of these approaches for FSW populations has not been assessed.
Although clandestine FSW in this study reported nearly universal consistent condom use with either new or regular clients, much lower levels were reported for noncommercial sex partners such as a regular partner or “friend.” Similar condom use differentials have been reported elsewhere in the region [24
]. Yet, of the 162 women who reported vaginal symptoms in this study, a minority informed their sexual partner and only 56% avoided sex. These findings highlight the need to address both the potential STI transmission to and the burden of STI among stable partners of FSWs, themselves a potential bridge population to lower risk segments of the general population [5
The reproductive health profile of participants revealed an average of 2.5 pregnancies (SD = 1.3). Although reported condom use in the context of commercial sex was high, complementary use of contraceptive methods was lacking. Patterns indicate that condoms are perceived principally as STI prevention rather than a family planning method. An integral part of the STI prevention message is the distribution of free condoms at STI clinics. Thus survey response on condom use as a contraception method may reflect the lack of integration between STI prevention and family planning programs in Peru with respect to these interrelated behavior change objectives.
Abortion in Peru is illegal thus limiting our ability to understand the prevalence of unsafe abortions and their impact on maternal morbidity and mortality [35
]. Previous studies estimated the Peruvian abortion rate to be one of the highest in Latin America [38
]. The 68% of ever pregnant women reporting having had at least one abortion is higher than the 53% reported for 514 Columbian FSWs [40
]. Given the self-medication behavior through pharmacies as reported in our study and the availability of medications including mifepristone and misoprostol (RU486), it is plausible that medical abortions are becoming more widely used by this population [41
]. This study supports the notion that FSWs are not only a vulnerable population due to GTI risk and their sequelae, but also because of an elevated risk of reproductive health problems. These risks likely arise from a constellation of disadvantages including limited access to reproductive health information, possible unmet demand for family planning methods and the cumulative effect of seeking to terminate unwanted pregnancies. (Public health polices related to FSWs have not changed in the past 10 years, and family planning is currently not included in the protocol of STI clinical exams for FSWs [42
]. Requesting reproductive health information requires a separate appointment, often at a different clinic.).