The Population Council is developing vaginal rings to prevent sexual transmission of HIV and other STIs, as well as unintended pregnancy.
Women have numerous contraceptive choices, including birth control pills, patches, implants, IUDs, and vaginal rings. But for women who also want to prevent infection with HIV and other STIs, choices are limited to condoms, which can be difficult to negotiate with partners and may not be practical for women and couples who want to have children.
The Council is developing two sustained-release combination microbicide rings: one that will prevent the sexual transmission of HIV and other STIs, and another that will prevent HIV, other STIs, and unintended pregnancy.
- Preventing HIV and STIs: The Council has developed a ring that contains the antiretroviral MIV-150 (an enzyme inhibitor that prevents infected cells from producing new virus), zinc acetate (a broad-spectrum antiviral agent), and carrageenan (a natural polymer isolated from seaweed that also has broad-spectrum antiviral properties). This ring, known as the MZC intravaginal ring, was designed to prevent the acquisition and transmission of HIV and other STIs such as herpes simplex virus (HSV-2), human papillomavirus (HPV), and Trichomonas vaginalis. It is intended for 90 days of use by women who want continuous protection from HIV and other STIs.
- Preventing pregnancy, HIV, and STIs: The Council has also developed a ring containing the MZC microbicide and levonorgestrel (a licensed contraceptive). The MZCL intravaginal ring is intended for women who want the continuous protection from HIV and other STIs delivered by the MZC ring with the added benefit of a contraceptive to prevent unintended pregnancy.
Council researchers and external collaborators have manufactured prototype MZC and MZCL intravaginal rings and extensively tested their performance in in vitro (in cells and tissues) and in vivo (in animals) studies. They have shown that the MZC and MZCL rings release useful amounts of MIV-150, zinc acetate, carrageenan, and levonorgestrel in vitro and in vivo. Initial efficacy studies in macaques show promise for these dual-protection methods.
A safe and effective intravaginal ring would allow women to protect themselves from HIV, STIs, and unintended pregnancy and make a major contribution to global public health.