Initiation of ART leads to a rapid decline in cervical and vaginal HIV-1 RNA

Decreased genital HIV-1 RNA shedding in women is associated with lower risk of both mother to child transmission and probably heterosexual transmission. A poster by Susan Graham and coworkers reported findings from an evaluation of genital HIV-1 RNA shedding in women in women initiating antiretroviral therapy.

This study, conducted in Mombassa, Kenya, compared HIV-1 RNA decay rates in blood plasma, cervical and vaginal secretions during the first month of receiving treatment. A group of 20 drug naive female sex workers participated after initiation of antiretroviral treatment of d4T, 3TC and nevirapine.

Intensive sampling was performed and interviews and examinations were conducted at each visit. Samples were collected on days 0, 2, 7, 14, and 28 for blood plasma and days 0, 1, 2, 4, 7, 14, and 28 for genital swabs. RNA levels at different time points were compared.

The authors reported excellent adherence levels, median 100% (range 98.9 -100%). On day 0, the median blood plasma HIV-1 RNA was 5.4 log copies/mL (IQR, 5.0-5.9 log copies/mL) and CD4 count 120 cells/mm³ (IQR, 58 -161 cells/mm³). All women had genital HIV-1 RNA shedding at baseline, with median 3.7 log10 copies/swab (IQR, 3.0 – 4.5 log copies/swab) in cervical secretions and 3.8 log1 copies/swab (IQR, 3.1 – 4.5 log copies/swab) in vaginal secretions.

They observed significant decreases by day 2 in blood plasma (p<0.001) and in cervical secretions (p = 0.001) and by day 4 in vaginal secretions (p <0.001).

They found the Initial decay rates in blood plasma, cervical, and vaginal compartments were 0.6, 0.8, and 1.2 log virions per day. Subsequent decay rates were 0.04, 0.05, and 0.06 log virions per day, respectively. They also reported a significantly faster initial decay rate for vaginal HIV-1 RNA shedding than for blood plasma (p = 0.02). At day 28, 19 women had detectable HIV-1 RNA in blood plasma (range 2.2-4.3 log copies/mL), 6 in cervical secretions (range, 1.7-3.1 log copies/swab) and 4 in vaginal secretions (range, 2.1-3.1 log copies/swab).

They concluded: Genital HIV-1 RNA shedding decreased rapidly after ART initiation, but 7 of 20 women had detectable genital HIV-1 shedding after 1 month of ART. These findings are consistent with a rapid decrease in infectivity. However, persistent genital HIV-1 shedding may indicate an ongoing risk of transmission by some women.

Graham S, Holte S, Richardson B et al. Initiation of ART leads to a rapid decline in cervical and vaginal HIV-1 RNA. 13th CROI, Denver, 2006. Abstract 130.