Microbicides are substances that are designed, when applied vaginally, to reduce transmission of HIV or other sexually transmitted infections (STIs). Some microbicides under development also function as spermicides to provide contraceptive protection. Eventually, microbicides are likely to be available as gels, creams, films, suppositories, or vaginal rings.

• Scientists currently are studying over 60 substances as possible microbicides. Some 45 of these substances are in laboratory or animal testing, and 17 are in various stages of human testing. Five are in or about to enter phase III clinical trials—the final stage of testing—which will determine how well these microbicide candidates prevent HIV infection and how safe they are for long-term use. If safety and effectiveness are established in clinical trials, a microbicide could be marketed perhaps as early as 2010 (26).



• Effectiveness remains uncertain. It is not yet known whether any of the five microbicides in phase III clinical trials will prove able to protect against HIV at all. If so, it may only be 50–60% effective in preventing HIV and other STIs, providing substantially less protection than condoms when used consistently and correctly. But future generations of microbicides are likely to be more effective than the first generation, less costly, and better able to meet people’s needs (106).



• Microbicides could save millions of lives. A vaginal microbicide that is used more consistently than condoms might prevent more HIV and STI infections than condoms do in actual use. Many sexually active people are at risk for HIV/AIDS because they do not use condoms or do not use them consistently and correctly, while people probably would be more likely to use microbicides than condoms. One estimate is that 2.5 million lives would be saved in the first three years after microbicides are introduced (28, 97).



• Women could control microbicide use. One advantage of microbicides over condoms is that women could use them without their partners’ cooperation. Microbicides would offer women, who often lack the power to control sexual activity or condom use, a method to reduce their vulnerability.



• Public interest could be substantial. Many women and men would have great interest in using microbicides, studies show. People differ widely, however, in the characteristics of the ideal microbicide they would prefer—a fact suggesting that manufacturers should provide a wide range of choices.



• Introduction strategy is crucial to access. For microbicides to fulfill their promise, they must be accessible and affordable. A successful introduction strategy would involve manufacturers, suppliers, public health systems, and governments and would include communication, marketing, logistics, and pricing plans.