(The Excerpt of) Potential Impact of Vaginal Microbicides on HIV Risk Among Women with Primary Heterosexual Partners

James M. McMahon, PhD, Associate Professor, Kathleen M. Morrow, PhD, Associate Professor, Margaret Weeks, PhD, Professor, Dianne Morrison-Beedy, PhD, RN, FNAP, WHAP, Professor and Dean, and Amanda Coyle, APRN, Senior Associate

Over the past 2 decades women have increasingly shouldered the burden of the global HIV pandemic (Joint United Nations Programme on HIV/AIDS [UNAIDS], 2004), with the majority of infected women acquiring HIV through sexual contact with a primary male partner (O’Leary, 2000). These trends are the result of multiple factors. Women may be biologically more susceptible to heterosexual transmission of HIV than men, especially via receptive anal intercourse (Boily et al., 2009; Mastro & Kitayaporn, 1998; Padian, Shiboski, & Jewell, 1991). 

In addition, gender-based social inequalities limit women’s options with regard to protective sexual behavior (Higgins, Hoffman, & Dworkin, 2010; Quinn & Overbaugh, 2005; Remien, Halkitis, O’Leary, Wolitski, & Gomez, 2005). Latex condoms, currently the only effective form of barrier protection against HIV, are under the control of men, who often are unwilling to use them, especially in the context of primary relationships (Conley & Collins, 2005).

Vaginal microbicides represent a female-initiated form of barrier and/or chemical protection that can potentially empower women with a means of self-protection. Vaginal microbicides are self-administered chemical compounds, most commonly in the form of a gel, that women can apply intravaginally prior to sexual intercourse to prevent or reduce HIV transmission. Modeling studies indicate that even a partially effective microbicide could have a major impact on the global HIV pandemic (Watts, 2002). 

While it is anticipated that the first generation of vaginalmicrobicides will be less effective at preventing HIV than latex condoms, the enormous potential of this new technology lies in its enhanced acceptability and usability by women. As our experience with the female condom has demonstrated, the importance of the acceptability of any new HIV prevention technology cannot be overstated (Kaler, 2004). It is therefore critically important that the public health sector in the United States prepare for the introduction of commercially available vaginal microbicides (Van de Wijgert & Coggins, 2002). While many American women have expressed a keen interest in vaginal microbicides (Darroch & Frost, 1999), the issues surrounding their acceptability and preference in relation to condom use are complex and have not received adequate attention. One complexity involves the potential reduction of condom use that might result from the introduction and adoption of microbicides.

Because the first commercially available vaginalmicrobicides will most likely be less effective at preventing HIV than latex condoms, reductions in condom use concomitant with microbicide adoption—a phenomenon termed “condom migration”—could potentially lead to increases in HIV incidence (Foss, Vickerman, Heise, & Watts, 2003). The term thus implies that some women or couples might “migrate” away from condom use or replace condoms with the use of less effective microbicides. Thus, the impact of vaginal microbicides on the U.S. epidemic will not only depend on the efficacy of the microbicide but also on current rates of condom use in various risk groups, and on changes in condom use behavior following the adoption of microbicide products. 

The use and acceptability of condoms and vaginal microbicides for prevention of sexually transmitted infections (STI) is highly conditioned by relationship context. Short, Rosenthal, Auslander, and Succop (2009) found that young women in primary heterosexual relationships characterized by high relationship satisfaction were more likely to use a proxy microbicide. They concluded that future “…interventions to enhance (microbicide) uptake should consider the relationship context” (p. 313). Given the high rates of sexually transmitted HIV in African American and Latina women, especially from primary male partners, we examine issues of microbicide acceptability and condom migration in these risk groups and relationship contexts.

The primary aim of this report is to begin a dialogue that explores epidemiological, clinical practice, and policy implications concerning future dissemination and prevention guidelines related to anti-HIV vaginalmicrobicides among women at risk for HIV from a primary male partner. Specifically, we explored levels of risk and condom use among women from a high HIV-prevalent urban community, described women’s willingness to use a vaginalmicrobicide with a primary male partner, examined whether microbicide acceptability was influenced by level of microbicide efficacy, and described how microbicide adoption might affect condom use practices and risk reallocation (i.e., potential condom migration). Findings from this exploratory study, while based on a small sample, were supported by the literature and will serve to frame the discussion and illustrate how potential changes in condom use with the adoption of microbicides might alter HIV risk profiles among women in high-risk communities.

Conclusion

Given that 86% of our sample expressed a willingness to use vaginal microbicides with a primary partner and 77% endorsed protection against HIV as the reason for condom use, there was clearly a perceived need for HIV protection among women with primary sexual partners. However, if the high levels of condom migration among condom users in this sample is any indication of the larger population in high-prevalent communities, then the public health sector needs to become aware, informed, and prepared to implement policy decisions prior to the availability of commercial microbicides to address and avert any potential adverse consequences to public health. 

This exploratory study suggests that microbicide adoption coupled with subsequent reductions in condom use might result in an overall increase in HIV risk within specific groups of women in high-risk populations. While this conclusion is based on a small sample of women with primary male partners, it nonetheless underlines the need to examine these issues more carefully based on further empirical research and prepare an appropriate public health response.