The reasons for the rise in female cases differ among countries, with 97 percent of female HIV infections in the United States due to heterosexual transmission (81 percent) and intravenous drug use (16 percent). In the developing world, heterosexual transmission is responsible for nearly all of the infections among women, and mother-to-child transmission during childbirth further contributes to the spread of the disease.
Women are particularly vulnerable to such cultural factors as their relative lack of power in sexual relationships, widespread poverty, policies that deny women an education and tolerance of violence against women.
The excessive biological vulnerability to HIV among young women, is believed to be due to an immature genital whose mucosal lining is easier for the virus to penetrate; to hormonal factors, such as the use of birth control pills; and to a high incidence of sexually transmitted diseases, which inflame the female genital area and provide additional target cells for the virus to infect.
Quinn says that eventually societal changes will help, but immediate and faster action requires coordinated efforts to focus on women, develop effective microbicides that women can use themselves and a gender-specific vaccine program that takes into account the different immune responses between women and men.
Cultural programs are also needed for reshaping gender roles, such as educating more women about safe-sex practices, use of condoms, lessons on negotiating safe sex, and awareness campaigns about where to seek testing and treatment.
Quinn says that women are different when it comes to HIV infection, and if medical progr