HIV This Week

Drake AL, John-Stewart GC, Wald A, Mbori-Ngacha DA, Bosire R, Wamalwa DC, Lohman-Payne BL, Ashley-Morrow R, Corey L, Farquhar C. Herpes simplex virus type 2 and risk of intrapartum human immunodeficiency virus transmission. Obstet Gynecol 2007;109:403-9.

Drake and colleagues determined whether herpes simplex virus type 2 (HSV-2) infection was associated with risk of intrapartum human immunodeficiency virus type 1 (HIV-1) transmission and to define correlates of HSV-2 infection among HIV-1-seropositive pregnant women. The authors performed a nested case control study within a perinatal cohort in Nairobi, Kenya. Herpes simplex virus type 2 serostatus and the presence of genital ulcers were ascertained at 32 weeks of gestation. Maternal cervical and plasma HIV-1 RNA and cervical herpes simplex virus DNA were measured at delivery. Their results showed one hundred fifty-two (87%) of 175 HIV-1-infected mothers were herpes simplex virus 2 (HSV-2) seropositive. Among these 152 HSV-2-seropositive women, nine (6%) had genital ulcers at 32 weeks of gestation, and 13 (9%) were shedding herpes simplex virus in cervical secretions. Genital ulcers were associated with increased plasma HIV-1 RNA levels (P=.02) and an increased risk of intrapartum HIV-1 transmission (16% of transmitters versus 3% of nontransmitters had ulcers; P = .003), an association which was maintained in multivariable analysis adjusting for plasma HIV-1 RNA levels (P=.04). The authors found a borderline association for higher plasma HIV-1 RNA among women shedding HSV (P=.07) and no association between cervical herpes simplex virus shedding and either cervical HIV-1 RNA levels or intrapartum HIV-1 transmission (P=.04 and P=.05, respectively). The authors concluded that herpes simplex virus type 2 is the leading cause of genital ulcers among women in sub-Saharan Africa and was highly prevalent in this cohort of pregnant women receiving prophylactic zidovudine. After adjusting for plasma HIV-1 RNA levels, genital ulcers were associated with increased risk of intrapartum HIV-1 transmission. These data suggest that management of herpes simplex virus 2 (HSV-2) during pregnancy may enhance mother-to-child HIV-1 transmission prevention efforts.

Editors’ note: Genital herpes has been known for years to increase the risk of both HIV acquisition and transmission sexually so it is not surprising that it increases mother-to-child transmission. For overt genital ulceration detected during labour, Caesarean section is usually recommended to prevent neonatal herpes. Randomised controlled trials of herpes suppressive treatment to reduce HIV infectivity during sexual intercourse are underway however, clinical trials are also needed to assess whether long term herpes suppressive therapy in pregnancy will reduce mother-to-child transmission of HIV.