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

Objective: To investigate women's willingness to use vaginal microbicides to reduce/prevent HIV infection, using measures grounded in the individual, behavioral, and social contexts of sex.

Design: A cross-sectional study that enrolled a sample (N = 531) of 18-55 year old Latina, African-American, and White women in the U.S. between October, 2004, and July, 2005.

Main Outcome Measures: Willingness to use microbicides and individual- and context-related variables (e.g., demographics, relationship status).

Results: Exploratory and confirmatory factor analyses supported a one-dimensional, 8-item scale, with high internal consistency (alpha = .91). Subgroup analyses within the Latina (n = 166), African- American (n = 193), and White sub-samples (n = 172) also supported a unidimensional scale with strong internal validity and high reliability. Race/ethnicity as a contextual factor, a woman's history of using prevention products, and the nature of the sexual partnership were predictive of willingness to use microbicides (R = .41). That is, women with greater frequencies of condom use, a history of spermicide use, and non-main sexual partners had higher predicted Willingness to Use Microbicides scale scores, while White women had lower predicted scores.

Conclusion: The Willingness to Use Microbicides scale serves as the first psychometrically validated measure of factors related to microbicide acceptability. Developing and implementing psychometrically validated and contextualized microbicide acceptability measures, in an effort to understand microbicide users and circumstances of use, is crucial to both clinical trials and future intervention studies.