Willingness to use microbicides varies by race/ethnicity, experience with prevention products, and partner type.

Globally, approximately half of all new HIV infections occur in women and the proportion of newly infected women is increasing (Ogden, Ogden, Mthembu, & Williamson, 2004; UNAIDS/WHO, 2005). According to the Centers for Disease Control and Prevention [CDC], women represent approximately 30% of new infections in the United States (U.S.) each year, three-quarters of which are transmitted via heterosexual intercourse (Centers for Disease Control and Prevention [CDC], 2005). Among sexually active women, a woman's risk for HIV infection is often related to behaviors beyond her direct control, such as the sex- or drug-related behavior of a sexual partner (Hader, Smith, Moore, & Holmberg, 2001). Given the rise in the proportion of women becoming infected with HIV annually and the limited ability of women to exercise condom use with their male sexual partners (Beksinska, Rees, McIntyre, & Wilkinson, 2001; Parker, Easton, & Klein, 2000; Sapire, 1995; Smith, 2003; World Health Organization [WHO], 1997; Wingood & DiClemente, 1998), the need for a woman-initiated HIV prevention option is profound. Topical vaginal microbicides offer the best hope for protecting women from HIV/AIDS. The term “microbicide” applies to a range of products that, when applied topically to a woman's vagina prior to sexual intercourse, could prevent or significantly reduce HIV transmission; some may also provide protection against other STDs, and still others may have contraceptive effects (Alliance for Microbicide Development, 2004; Global Campaign for Microbicides, 2006; International Partnership for Microbicides, 2005). Several candidate vaginal microbicides are now undergoing clinical efficacy trials. In preparation for FDA approval of microbicides, behavioral and social scientists have been exploring psychosocial factors hypothesized to be associated with the acceptability and continued use of these products. It will be critical for successful uptake of the products, and thus their impact on rates of HIV transmission, to understand who would use microbicides and why. For instance, will product use vary by partner type or number, cultural influences on the sexual context, or other factors (Severy, Tolley, Woodsong, & Guest, 2005)? Given a greater understanding of which factors affect microbicide uptake and use, behavioral and social scientists, as well as health care providers and systems, will be better able to develop and target appropriate interventions. The Phoenix Project was designed to gather formative microbicide acceptability data to develop and psychometrically evaluate microbicide acceptability measures. Several health behavior models, including the theories of reasoned action and planned behavior, posit that behavioral intention, or the “subjective probability” that one will perform a given behavior (Fishbein & Ajzen, 1975), can predict eventual behavior. In one meta-analysis (Sheeran & Orbell, 1998), a medium to strong correlation was found between intentions and condom use, though the degree of relationship has been found to be affected by such factors as gender and partner type (Fishbein et al., 2001; von Haeften, Fishbein, Kaspryzk, & Montano, 2000). Thus, while some studies have found a significant relationship between measures of intention and measures of safer sex behavior (Albarracin, Johnson, Fishbein, & Muellerleile, 2001; Basen-Engquist, 1992; Basen-Engquist & Parcel, 1992; Bryan, Rocheleau, Robbins, & Hutchinson, 2005; Fishbein et al., 2001; Fisher, Fisher, & Rye, 1995; Godin, Gagnon, & Lambert, 2003; Posner, Bull, Ortiz, & Evans, 2004; Roberts & Kennedy, 2006; Sheeran, Abraham, & Orbell, 1999), others have found less evidence for such a relationship (Minnis, Shiboski, & Padian, 2003; Rosenthal, Fernbach, & Moore, 1997). It is possible that the way the construct is measured may contribute to these less than consistent results. Fishbein and colleagues (1975) discussed the need for specificity in items relating to intentions (i.e., behavior, target object, situation, and time). Within the realm of self-efficacy, Bandura (1985) and Forsyth and Carey (1998) posited the need to develop self-efficacy items that include a specific class of behavior and a specific context or circumstance. Studies of behavioral intentions have used measures with varying levels of specificity (Albarracin et al., 2001; Fishbein, Hennessy, Yzer, & Douglas, 2003), as have measures of self-efficacy (Smith, McGraw, Costa, & McKinlay, 1996). Gibbons and colleagues (1998) have postulated that distinct constructs of behavioral intention, willingness, and expectation should be considered when predicting behavioral outcomes. While, at face value, items measuring these constructs may appear very similar, Gibbons and colleagues have found them to contribute to the prediction of behavior, both together and independently. These results and the ongoing discussion of how best to contextualize the measurement of such constructs as intention and self-efficacy led the Phoenix Project to contextualize items related to willingness to use microbicide, specifying partner, partner type, and specific episode of sexual behavior, as well as specifying certain microbicide characteristics and accessibility referents. Willingness was chosen because of the still hypothetical nature of a microbicide, in contrast to intention and expectation, which imply an actual plan or goal, in an environment where proof of concept and, therefore, a readily available product, does not currently exist. Thus willingness, or the likelihood of using a microbicide under specific circumstances, best approximated the current status of microbicide development. As part of a larger effort to develop a set of microbicide acceptability measures for use in upcoming studies, the Phoenix Project gathered formative microbicide acceptability data to elucidate themes and constructs related to product use, developed quantitative items to measure those constructs, and tested the resulting measures. With respect to the current analysis, a measure of “willingness to use microbicides” was developed and evaluated. The resulting scale was then used in further analyses to explore demographic and other variables related to willingness to use microbicides. In the case of microbicide use, a woman's willingness to use a product under specific circumstances in the future may predict her actual use. Hence, willingness to use microbicides will ultimately affect the actual uptake and sustained use of a product. Our hypothesized model of acceptability assumes that product-related factors, as well as person-related factors, will be associated with a woman's willingness to use a microbicide.