by Rebecca Trager, Nature News, United Kingdom - Worldwide, an estimated 33 million people are living with HIV, roughly half of them women, according to UNAIDS. In South Africa, one in three women aged 20–34 is estimated to be infected with HIV. Because 60% of all new HIV infections in sub-Saharan Africa are in women, there is a sense of urgency surrounding the development of HIV-prevention tools for this group.