Genital tract HIV-1 RNA shedding among women with below detectable plasma viral load.

OBJECTIVE: Few studies have assessed longitudinal genital tract HIV-1 shedding. We determined patterns of genital tract HIV-1 RNA shedding over time among women with suppressed plasma viral load (PVL) on antiretroviral treatment.
METHODS: Paired plasma and genital tract HIV-1 RNA were measured every 4 weeks. Participants were classified as persistent, intermittent, or nonshedders. Longitudinal analysis examined rates of genital tract shedding and the association with PVL, CD4 cell count, and genital tract infections. Markov transition models were used to describe the dynamics of HIV-1 RNA in plasma and genital tract using visit-to-visit transitions from and to detectable and undetectable PVL or genital tract HIV-1 RNA.
RESULTS: Fifty-nine women contributed 582 study visits of whom 95 and 98% had below-detectable PVL and genital tract viral load, respectively, at baseline. Thirty-two of 59 women (54%) had detectable HIV-1 RNA at least once in the genital tract. Twenty-two of 59 (37%) women had detectable genital tract HIV-1 RNA during a study visit when PVL was undetectable; 6.8% of the women were persistent shedders, 31% were intermittent shedders, and 45.8% were nonshedders. Sampling three subcompartments increased detection of HIV-1 genital tract viral load compared to sampling a single subcompartment. Overall, genital tract HIV-1 RNA shedding in any subcompartment occurred at about 13% of visits. Shedding in at least one of the three subcompartments occurred at 9% of visits when PVL was undetectable (95% confidence interval 6-14%).
CONCLUSION: Women with below-detectable PVL may have less risk of HIV sexual transmission on a population level, but may continue to be infectious on an individual level.