This page on the website of the International Partnership for Microbicides (IPM) provides information and links to resources about The Ring Study, a clinical trial designed to determine whether a monthly vaginal ring that delivers the antiretroviral drug dapivirine helps prevent HIV infection in women and is safe for long-term use. The Ring Study, which enrolled 1,959 women at six sites in South Africa and one site in Uganda, was one of two trials of the dapivirine ring to demonstrate a protective effect against HIV.