Hormonal contraceptive use, herpes simplex virus infection, and risk of HIV-1 acquisition among Kenyan women
Polly Clayden, HIV i-Base
There have been conflicting results from studies evaluating the effect of hormonal contraceptive use on the risk of HIV acquisition.
Recent data from a study conducted in Uganda and Zimbabwe found that women using hormonal contraception had an increased risk if they were herpes simplex virus type 2 (HSV-2) negative, but not if they were HSV-2 positive. This difference in risk was highly significant (p=0.003).
A paper in the August 20 2007 edition of AIDS authored by Jared Baeten and coworkers reported findings from a study to examine the effect of HSV-2 on the relationship between hormonal contraception and HIV-1 in a high-risk population. 
This group had previously found in a study of female Kenyan sex workers, both oral contraceptive pill and depot medroxyprogesterone acetate (DMPA) use were associated with increased risk of HIV aquisition. . HSV-2 was not assessed in that analysis. The investigators re-examined the data to evaluate the effect of HSV-2 on the relationship between hormonal contraception and HIV.
Data were from a prospective cohort study of 1206 HIV-negative sex workers from Mombasa, Kenya who were followed monthly.At enrolment, 171 (14.2%) women used oral contraceptive pills and 244 (20.2%) DMPA. 234 (19.4%) women were HSV-2 negative and 972 (80.6%) were HSV-2 positive. 84 women who were HSV-negative at enrolment seroconverted during the study period.
The investigators found 233 women acquired HIV-1 (8.7/100 person-years). HSV-2 prevalence (81%) and incidence (25.4/100 person-years) were high. In multivariate analysis, including adjustment for HSV-2, HIV acquisition was associated with use of oral contraceptive pills [adjusted hazard ratio (HR), 1.46; 95% confidence interval (CI), 1.002.13] and DMPA (adjusted HR, 1.73; 95% CI, 1.282.34).
The effect of hormonal contraception on HIV acquisition was not significantly different between HSV-2 negative versus positive women. HSV-2 infection was associated with increased HIV risk (adjusted HR, 3.58; 95% CI, 1.647.82).
The investigators concluded: In this group of high-risk African women, hormonal contraception and HSV-2 infection were both associated with increased risk for HIV-1 acquisition. HIV-1 risk associated with hormonal contraceptive use was not related to HSV-2 serostatus.
- Baeten JM, Benki S, Chohan V et al. Hormonal contraceptive use, herpes simplex virus infection, and risk of HIV-1 acquisition among Kenyan women. AIDS 2007, 21:17711777
- Lavreys L, Baeten JM, Martin HL et al. Hormonal contraception and risk of HIV-1 acquisition: results of a 10-year prospective study. AIDS 2004; 18:695697.