Microbicides in HIV prevention

In 1999 about 5.4 million people were newly infected with HIV.1 In some countries public health programmes have achieved modest gains in reducing HIV transmission through behavioural change, but the worldwide picture is one of increasing rates of infection. Although the use of condoms has slowly increased in countries most severely affected by the HIV epidemic, many vulnerable women are unable to ensure they are used. An effective and affordable vaginal microbicide, whose use could be controlled by women, would represent an important addition to the armamentarium against HIV infection. In this article we examine current progress in microbicide development and discuss their future role in HIV control. We searched Medline using the key words and phrases “microbicides,” “virucides,” and “vaginal microbicides.” We also obtained the latest product information from the Alliance for Microbicide Development (P Harrison, personal communication),2 and we asked scientific colleagues involved in microbicide research for their comments on products in preclinical development. Microbicides act by disrupting or disabling organisms or block their entry into host cells by interfering with cell surface receptors. Chemical agents have a long history in the control of sexually transmitted infections and fertility. Penile antiseptics were widely promoted for controlling sexually transmitted disease in both world wars, although their efficacy and effectiveness remain uncertain.3 Intravaginal spermicides have been marketed for decades but have had limited popularity in the era of more reliable contraceptive methods. The development of microbicides has drawn on existing contraceptive technology to develop safe, effective, acceptable, and accessible agents. As with HIV vaccines, progress with the development of effective microbicides has been slow, and the results of early trials of surfactants such as nonoxinol 9 were disappointing. The Microbicides 2000 conference in Washington, DC, provided new impetus to develop such compounds, and several promising products are …