Several microbicide candidates have been ruled out through large-scale effectiveness trials that have helped guide the field of microbicide research toward more promising products. Two trials have shown that a vaginal ring containing the antiretroviral drug dapivirine is safe to use and reduces women's risk of HIV acquisition. Trials of other potential microbicides, including a rectal formulation of tenofovir gel, are ongoing.

Resources with information about all completed effectiveness (Phase IIb and Phase III) trials of microbicide candidates are listed on the study product pages. Additional products that are being evaluated are described on the Current and Planned Trials page of the toolkit. For another up-to-date summary of microbicide effectiveness trials and their results, see AVAC's HIV Prevention Research and Development Database.