Hormonal contraceptive use, herpes simplex virus infection, and risk of HIV-1 acquisition among Kenyan women

2 October 2007. Related: Women's health.

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. [1]

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. [2]. 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), 1.00–2.13] and DMPA (adjusted HR, 1.73; 95% CI, 1.28–2.34).

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, 1.64–7.82).

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.”

References:

1. 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, 21:1771–1777
2. 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; 18:695–697.