Recently, a volume of research has been undertaken to define survival, disease progression, access to care, and prognostic markers for HIV-infected women.
Although early reports [2, 3] found that male sex appeared to confer a survival benefit in AIDS, later studies, which controlled for access to care, antiretroviral use, and disease stage, found similar rates of progression and survival for both sexes [4–7].
We undertook a critical epidemiological review of the available evidence concerning whether women have lower levels of human immunodeficiency virus (HIV) RNA than do men at similar stages of HIV infection.
The 13 studies included in this analysis reported viral load measurements in HIV-infected men and women at a single point in time (cross-sectional studies) or over time (longitudinal studies).
Seven of the 9 cross-sectional studies demonstrated that women had 0.13–0.35 log (2- to 6-fold) lower levels of HIV RNA than do men, even when controlling for time since seroconversion.
Adjustment for possible confounders of the relationship between sex and viral load, including age, race, mode of virus transmission, and antiretroviral therapy use, did not change this outcome.
A putative finding that women progress to AIDS at rates similar to those for men but from lower viral load set points has implications for HIV management and mechanisms of viral pathogenesis in women.
We report the results of a critical review of the evidence regarding the effects of sex on viral load, with an exploration of the significance and biological plausibility.We searched the MEDLINE database for studies from 1995–2000 that examined the relationship between a patient's sex and viral load, using permutations of the keywords “HIV,” “viral load,” “HIV RNA,” “women,” “gender,” and “sex”; the search was restricted to articles in the English language that involved human subjects. The MEDLINE search was repeated for articles from 1990–1994, from which we identified 39 additional articles.This finding is significant, because viral loads are frequently used to guide the initiation and modification of antiretroviral therapy.Recent UNAIDS statistics report that women constitute 47% of adults living with HIV/AIDS worldwide.In the United States, the number of prevalent AIDS cases among women is steadily increasing; the Centers for Disease Control and Prevention  now estimate that 23% of the reported AIDS diagnoses occur in women.Women also represent the fastest-growing group with incident HIV infection, with the highest rates being among black and Hispanic women.