Treating Sexually Transmitted Infections (STIs)

Worldwide, the burden of sexually transmitted infections in women is more than five times that in men (Sciarra, 2009). Multiple observational studies have found an association between STIs and HIV (Venkatesh et al., 2011b; Cohen and Eron, 2011; Mavedzenge et al., 2010b; Weber et al., 2010). A recent study found that the odds of acquiring HIV were 2.4 times higher in women with prior cervical HPV infection after adjustment for both behavioral and biologic risk factors (Averbach et al., 2010).

However, the evidence that treating STIs can reduce the spread of HIV to women has been generally disappointing (Padian et al., 2010; Celum et al., 2010). A Cochrane review from 2011 noted: "We failed to confirm the hypothesis that STI control is an effective HIV prevention strategy" (Ng et al., 2011: 2). The only study to show an impact on HIV incidence from STI treatment has been the Mwanza trial in Tanzania. A combination of improved STI treatment services was shown to reduce HIV incidence in an environment characterized by an emerging HIV epidemic (low and slowly rising prevalence), where STI treatment services are poor, and where STIs are highly prevalent (Grosskurth et al., 1995). The other eight trials of STI treatment have shown no effect on HIV acquisition (Padian et al., 2010).

One hypothesis for why improved STI treatment services reduced HIV incidence in Mwanza but not elsewhere was that "... the Mwanza trial was implemented in an earlier phase HIV epidemic than was the case for the five [trials that showed no results]..., all of which were conducted in late-phase, generalized epidemics when genital herpes had largely replaced curable etiologies of genital ulcers, while rates of other curable STIs had fallen substantially in the general population" (Padian et al., 2010: 629). Treating STIs as a way to reduce HIV transmission begs the question: "is the juice worth the squeeze?" (Cohen and Eron, 2011: 410) that is, is treating STIs too far removed as a strategy for HIV prevention given that there are more direct prevention methods available? Given the recent study showing that antiretroviral therapy can reduce HIV transmission (Cohen et al., 2011b), it may not, indeed, be worth the squeeze. However, "notwithstanding, the inconsistent findings from these randomized controlled trials, the significant reproductive health challenge posed by the high burden of curable STIs needs to be addressed in any HIV prevention effort" (Abdool Karim et al., 2010a: S122). From a policy perspective, treatment of curable STIs is an essential part of primary health care. In addition, STI clinical services offer important entry points for provision of HIV prevention services (Hayes et al., 2010b).

Using STI services as a point of access to reach women at high risk of acquiring HIV is important both to offer HIV testing and counseling and as a gateway to HIV treatment and care (WHO et al., 2011b). These services "contribute to the achievement of universal access to HIV prevention by promoting condom use, behavioral change and the empowerment of vulnerable populations" (Chersich and Rees, 2008: S35). "Even if in the end it is found that STDs have only a limited impact on HIV transmission, we cannot afford to miss the potentially cost-effective chance of controlling HIV through their treatment. Additionally, STDs are important diseases, which by themselves cause major morbidity and reduced fertility, demanding control" (Rottingen et al., 2001: 594).

Treatment of sexually transmitted infections is also critically important for women living with HIV. STIs in those who are HIV-positive may be associated with faster disease progression and may contribute to greater HIV transmission and thus is treating STIs is an important component of meeting the sexual and reproductive health needs of women living with HIV. [See Meeting the Sexual and Reproductive Health Needs of Women Living With HIVand Preventing, Detecting and Treating Critical Co-Infections]