A vaginal ring has shown promise in protecting against HIV, genital herpes, human papillomavirus (HPV) and pregnancy in a primate study. Researchers gave rhesus macaque monkeys vaginal rings containing either a placebo or various combinations of agents, including: levonorgestrel as a contraceptive; and a combination therapy called MZC to protect against SHIV (an HIV-like human-monkey hybrid virus), HPV and herpes symplex virus type 2 (HSV-2). Next, the monkeys were repeatedly exposed to SHIV and HSV-2. Four of the 12 monkeys with the rings containing MZC plus levonorgestrel acquired SHIV. Meanwhile, all four of the monkeys with the rings containing just the contraceptive and two out of four monkeys that received the placebo rings contracted SHIV.  Data also suggested that the rings with MZC lowered the risk of HSV-2 by 25 percent. Tests of the blood levels of the preventive elements suggested the rings may also help prevent pregnancy and HPV.