Women May Have High HIV Levels in Genital Tract Even if Virus Appears Suppressed in Blood Tests

Women whose blood work shows low levels of HIV may still be at risk of transmitting the virus to their sexual partners or infants because of high viral levels found in the genital tract, according to a study in the Nov. 10 issue of the Lancet. From Jan. 30, 1997, to July 1, 1998, Dr. Andrea Kovacs of the Keck School of Medicine at the University of Southern California and colleagues conducted a cross-sectional study of 311 HIV-positive heterosexual women and found that even when women's blood viral loads had been suppressed to fewer than 500 copies/mL, a third of the women had high levels of HIV in their genital tracts. The women -- most of whom were black, between the ages of 19 and 45, had experienced two or more pregnancies and were on antiretroviral therapy -- were participating in the Women's Interagency HIV Study. The researchers took medical histories, conducted clinical assessments, cultured HIV-1 and measured HIV RNA in peripheral blood mononuclear cells (PBMC) and genital secretions.

Findings
Fifty-seven percent of the women had HIV-1 RNA present in their genital secretions and infectious virus was detected in 6% of the women. Genital tract HIV-1 shedding was found in 80% of the women with detectable levels of plasma RNA and 78% of the women with positive PBMC cultures. Thirty-nine percent of those with negative PBMC cultures also exhibited genital tract shedding. Plasma RNA concentration was the "most important factor" for predicting genital HIV-1 shedding. According to the authors, "[n]o other factor, including CD4 cell count or genital tract infections or abnormalities were predictive" of viral shedding.

Implications
The presence of viral genital shedding in women with low plasma HIV RNA loads "suggest[s] a separate reservoir of HIV-1 replication" (Kovacs et al., Lancet, 11/10). Kovacs said it is possible that HIV "preferentially replicates" in the genital tract in some people. However, it is also possible that antiretroviral drugs do not "fully control" some "local" virus reservoirs in the body. The finding is especially important for pregnant women with HIV who may transmit the virus to their newborn infants through "direct" contact with genital secretions during delivery (Norton, Reuters Health, 11/9). In an accompanying commentary, Dr. Pietro Vernazza of Cantonal Hospital in St. Gallen, Switzerland, states that genital viral load "might serve as a better estimate for [HIV] transmission" and "patients will have to continue to be warned about the consequences of unprotected sex even if blood tests indicate that they have responded to antiretroviral therapy" (Vernazza, Lancet, 11/10).