Maternal herpes simplex virus type 2 coinfection increases the risk of perinatal HIV transmission : possibility to further decrease transmission?

The objectives were to evaluate the association between maternal herpes simplex virus type 2 seropositivity and genital herpes simplex virus type 2 shedding with perinatal HIV transmission. Evaluation of women who participated in a 1996-1997 perinatal HIV transmission prevention trial in Thailand. In this nonbreastfeeding population women were randomized to zidovudine or placebo from 36 weeks gestation through delivery; maternal plasma and cervicovaginal HIV viral load and infant HIV status were determined for the original study. Stored maternal plasma and cervicovaginal samples were tested for herpes simplex virus type 2 antibodies by enzyme-linked immunoassay and for herpes simplex virus type 2 DNA by real-time PCR respectively. Among 307 HIV-positive women with available samples 228 (74.3%) were herpes simplex virus type 2 seropositive and 24 (7.8%) were shedding herpes simplex virus type 2. Herpes simplex virus type 2 seropositivity was associated with overall perinatal HIV transmission [adjusted odds ratio 2.6; 95% confidence interval 1.0-6.7)] and herpes simplex virus type 2 shedding was associated with intrapartum transmission (adjusted odds ratio 2.9; 95% confidence interval 1.0-8.5) independent of plasma and cervicovaginal HIV viral load and zidovudine treatment. Median plasma HIV viral load was higher among herpes simplex virus type 2 shedders (4.2 vs. 4.1 log10 copies/ml; P = 0.05) and more shedders had quantifiable levels of HIV in cervicovaginal samples compared with women not shedding herpes simplex virus type 2 (62.5 vs. 34.3%; P = 0.005). We found an increased risk of perinatal HIV transmission among herpes simplex virus type 2 seropositive women and an increased risk of intrapartum HIV transmission among women shedding herpes simplex virus type 2. These novel findings suggest that interventions to control herpes simplex virus type 2 infection could further reduce perinatal HIV transmission. (authors)