A FACTORIAL SURVEY STUDY TO ASSESS THE ACCEPTABILITY OF HIV VACCINE TRIAL DESIGNS

To aid in the design of human immunodeficiency virus (HIV) vaccine tri als that maximize volunteer participation, factorial surveys were admi nistered to 73 gay men who were participants in a larger study assessi ng HIV vaccine trial feasibility. Factorial surveys are ''vignettes'' that are randomly constructed through the combination of descriptive s tatements (dimensions) that reflect essential features. In this study, the dimensions define components of clinical trials to assess the eff icacy of hypothetical HIV vaccines. Regression analysis shows that ant icipated participation was decreased by a sustained vaccine-induced an tibody response lasting 3 years, absence of gay men as research subjec ts in earlier phase trials for the products being tested, and rectal V accine administration. Three years of scientific experience with the v accine encouraged participation. We conclude that willingness to parti cipate in vaccine trials varies systematically with some of their char acteristics. Where there are design alternatives for identified negati ve components, these should be considered. If this is not possible, op tions for decreasing aversion to such features will need to be evaluat ed, including appropriate education regarding both the benefits and th e risks associated with negatively evaluated features.