Update on microbicide research and development-seeking new HIV prevention tools for women

Current HIV incidence rates in highly impacted regions reflect the magnitude of the epidemic and point out an apparent lack of HIV prevention methods, specifically for women. Sixty-eight percent of the 2.3 million adults newly infected with HlV in 2008 live in sub-Saharan Africa, where approximately 60% of infected individuals are women [1]. Women and adolescent girls are especially vulnerable to HIV infection in sub-Saharan Africa not only because of their increased physiological susceptibility to heterosexual transmission, but also because of social, legal, and economic disadvantages [1]. According to the most recent estimate, the number of people living with HIV is 33.4 million [1]. In the nine countries in southern Africa affected most by HIV (Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia, and Zimbabwe), prevalence among young women aged 15-24 years was reported to be approximately 3 times higher than among men of the same age [2]. HIV prevention options for women are presently limited in this setting.Microbicides to prevent HIV infection in women are vaginally applied topical products that interfere with HIV infection at one or more steps in the replication cycle. This paper summarizes research to date on early generation product development efforts (polyanions, surfactants, acidifying agents) and next generation antiretroviral (ARV)-based HIV microbicides and introduces the concept of pre-exposure prophylaxis (PrEP) for the prevention of HIV transmission.Half of the exposed population currently has no effective means of self-initiated HIV prevention; and although condoms provide good protection from HIV infection, their regular use is not always negotiable by women. The effectiveness of an HIV prevention method is impacted by its correct and consistent use. Therefore, microbicide research and development has also focused on the topic of adherence, and factors affecting adherence, such as preferred dosage forms and regimens, st