Recent biomedical developments for HIV pre-exposure prophylaxis (PrEP) have highlighted both successes and challenges with daily or peri/pre-coital use of antiretroviral (ARV)-based prevention methods (1,2). Several topical and oral effectiveness PrEP trials yielded divergent results, mainly attributed to varying levels of product adherence within and across trials. These results highlight that ARV-based prevention approaches are highly dependent on correct dosing to achieve adequate protection (3). These approaches have aptly been coined “bio-behavioral,” as individuals have to adjust their behavior to incorporate correct use of these products into their lives and the technologies have to be developed to fit with people’s lives and behaviors (4,5).Worldwide, women continue to be disproportionately affected by HIV (6) thus the search for novel, acceptable female-initiated methods remain an important priority. Microbicide vaginal rings can offer sustained single or multidrug topical delivery that can simplify use and improve product effectiveness. Rings offer several advantages over the applicator-and-gel approach, such as continuous use for one to several months and coital independence of product application (7); thus rings have the potential to increase product adherence, acceptability, and effectiveness. Previous studies in Africa have shown overall high acceptability and high reported adherence to vaginal rings for HIV prevention (8–11). Two Phase III trials are ongoing in Africa, testing the safety and effectiveness of a vaginal ring containing 25 mg of dapivirine (DPV), a non-nucleoside reverse transcriptase inhibitor (12,13).In Europe, the United States, and most recently in South Africa, vaginal rings are currently used for contraception (14). Rings are also used for treatment of symptoms related to menopause. Studies have repeatedly shown high acceptability among women who use NuvaRing®, a combined hormonal contraceptive ring, both in the United States and abroad (15–17). In a European study, sexual comfort was reportedly high and 15% of women and 29% of partners felt the ring during intercourse at least occasionally (15). In one comparative study between NuvaRing and oral contraceptives with young women in the United States, the ring’s overall acceptability was good (65%) however, more women thought that the ring, compared with the pill, interfered with sex and fewer partners liked the ring (18). In contrast, in another United States-based comparative study, women preferred the vaginal ring to both the contraceptive patch and oral contraceptives (5). Thus, in preparation for the introduction of a vaginal ring as a novel HIV prevention method, it is critical to understand the acceptability of various product attributes as well as users’ experiences and skills needed for correct and consistent use in a range of settings.
Application of a composite measure of product adherence, protocol compliance, and semen exposure to a phase III microbicide HIV prevention trial
