a systematic review conducted in 2019 was unable to find conclusive evidence that prep use increases sexual risk behaviors, and found that prep may provide an opportunity for msm to access sexual health care, testing, treatment and counselling services. emerging treatments although hiv prep medications are only available in oral tablet and injectable formulations, other formulations are being developed and studied. the emerging treatments expand hiv prevention strategies for women. for example, a vaginal gel formulation of tenofovir and an intravaginal ring releasing dapivirine are under investigation for efficacy. out of three completed trials evaluating safety and efficacy of tenofovir vaginal gel, only the caprisa 004 trial showed the drug to be efficacious in decreasing the risk of hiv infection. however, the demonstrated effectiveness of tenofovir vaginal gel was deemed not significant enough to move forward with the product. in contrast, the aspire study and the ring study evaluating the dapivirine-releasing intravaginal ring have demonstrated efficacy in reducing incidence of hiv infection. in addition to these two treatments, an injectable form of cabotegravir is being evaluated for efficacy in the hptn 03 and hptn 04 trials.