HIV/AIDS and U.S. Women Who Have Sex With Women (WSW)

Female-to-female transmission of HIV appears to be a rare occurrence. However, case reports of female-to-female transmission of HIV and the well documented risk of female-to-male transmission of HIV indicate that vaginal secretions and menstrual blood are potentially infectious and that mucous membrane (e.g., oral, vaginal) exposure to these secretions have the potential to lead to HIV infection.

What do surveillance tools tell us about transmission between women?

Through December 1998, 109,311 women were reported with AIDS. Of these, 2,220 were reported to have had sex with women; however, the vast majority had other Picture risks (such as injection drug use, sex with high-risk men, or receipt of blood or blood products). Of the 347 (out of 2,220) women who were reported to have had sex only with women, 98% also had another risk -- injection drug use in most cases.

Note: information on whether a woman had sex with women is missing in half of the 109,311 case reports, possibly because the physician did not elicit the information or the woman did not volunteer it.

What do investigations of female-to-female transmission show?

Women with AIDS whose only reported risk initially is sex with women are given high priority for follow-up investigation. As of December 1998, none of these investigations had confirmed female-to-female HIV transmission, either because other risks were subsequently identified or because, in a few cases, women declined to be interviewed. A separate study of more than 1 million female blood donors found no HIV-infected women whose only risk was sex with women. These findings suggest that female-to-female transmission of HIV is uncommon. However, they do not negate the possibility because it could be masked by other behaviors.

What are the behaviors that place WSW at risk of HIV infection?

Surveys of risk behaviors have been conducted in groups of WSW. These surveys have generally been surveys of convenient samples of WSW that differ in sampling, location, and definition of WSW. As a result, their findings are not generalizable to all populations of WSW. These surveys suggest that some groups of WSW have relatively high rates of high-risk behaviors, such as injection drug use and unprotected vaginal sex with gay/bisexual men and injection drug users.

What can WSW do to reduce their risk of contracting HIV?

Although female-to-female transmission of HIV apparently is rare, female sexual contact should be considered a possible means of transmission among WSW. These women need to know:

  • that exposure of a mucous membrane, such as the mouth, (especially nonintact tissue) to vaginal secretions and menstrual blood is potentially infectious, particularly during early and late-stage HIV infection when the amount of virus in the blood is expected to be highest.


  • that condoms should be used consistently and correctly each and every time for sexual contact with men or when using sex toys. Sex toys should not be shared. No barrier methods for use during oral sex have been evaluated as effective or approved by the FDA. However, women can use dental dams, cut-open condoms, or plastic wrap to help protect themselves from contact with body fluids during oral sex.

  • their own and their partner's HIV status. This knowledge can help uninfected women begin and maintain behavioral changes that reduce their risk of becoming infected. For women who are found to be infected, it can assist in getting early treatment and avoiding infecting others.

Health professionals also need to remember:

  • that sexual identity does not necessarily predict behavior, and that women who identify as lesbian may be at risk for HIV through unprotected sex with men.

  • that prevention interventions targeting WSW must address behaviors that put WSW at risk for HIV infection, including injection drug use and unprotected vaginal-penile intercourse.

For information about national HIV prevention activities, see the following CDC fact sheets:

For more information...

CDC National AIDS Hotline:
Spanish: 1-800-344-SIDA
Deaf: 1-800-243-7889

CDC National Prevention Information Network:
P.O. Box 6003
Rockville, Maryland 20849-6003

Internet Resources: