Vaginal Viral Shedding with Undetectable Plasma HIV Viral Load in Pregnant Women Receiving Two Different Antiretroviral Regimens: A Randomized Clinical Trial.

BACKGROUND Pregnant women using antiretrovirals (ART) may have persistent vaginal virus shedding, which could be associated with sexual and perinatal HIV transmission.However, there is scant data on on vaginal viral load (VVL) in pregant women with undetectable plasma viral load (PVL). METHODS This study was a post-hoc analysis of an open-label randomized trial to evaluate the virologic response of two ART regimens. The participants were ART-naive women living with HIV initiating ART regimens between 20 and 36 weeks of pregnancy recruited at 19 clinical sites in six countries. Participants were randomized to receive raltegravir 400 mg BID or efavirenz 600 mg QD in addition to lamivudine 150 mg and zidovudine 300 mg BID. VVL and PVL tests were performed at every study visit. The primary outcomes measures were HIV-1 PVL and VVL at maternal study week 4 and rates of perinatal HIV transmission. RESULTS A total of 408 were enrolled, of whom 323 had VVL samples 4 weeks after enrollment and were included in this analysis. Among women with undetectable/non-quantifiable PVL during ART, the overall rate of quantifiable VVL at Week 4 was 2.54% (7/275). Of the 275 with non-quantifiable PVL, 99.1% (115/116) and 96.2% (153/159) had non-quantifiable VVL in the EFV and RAL arms, respectively. None of the seven women with quantifiable VVL at the week 4 study visit transmitted HIV to their infants. CONCLUSIONS Detectable VVL in pregnant women with undetectable/non-quantifiable PVL while receiving ART was rare and not associated with perinatal HIV transmission.