Background: Studies of the effect of hormonal contraceptive use on the risk of HIV-1 acquisition have generated conflicting results. A recent study from Uganda and Zimbabwe found that women using hormonal contraception were at increased risk for HIV-1 if they were seronegative for herpes simplex virus type 2 (HSV-2), but not if they were HSV-2 seropositive.
Objective: To explore the effect of HSV-2 infection on the relationship between hormonal contraception and HIV-1 in a high-risk population. Hormonal contraception has previously been associated with increased HIV-1 risk in this population.
Methods: Data were from a prospective cohort study of 1206 HIV-1 seronegative sex workers from Mombasa, Kenya who were followed monthly. Multivariate Cox proportional hazards analyses were used to adjust for demographic and behavioral measures and incident sexually transmitted diseases.
Results: Two hundred and thirty-three 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-1 acquisition was associated with use of oral contraceptive pills [adjusted hazard ratio (HR), 1.46; 95% confidence interval (CI), 1.00–2.13] and depot medroxyprogesterone acetate (adjusted HR, 1.73; 95% CI, 1.28–2.34). The effect of contraception on HIV-1 susceptibility did not differ significantly between HSV-2 seronegative versus seropositive women. HSV-2 infection was associated with elevated HIV-1 risk (adjusted HR, 3.58; 95% CI, 1.64–7.82).
Conclusions: 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.
From the aDepartments of Medicine, USA
bEpidemiology, University of Washington, Seattle, USA
cDivisions of Human Biology, USA
dPublic Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, USA
eDepartment of Medical Microbiology, University of Nairobi, Kenya
fCoast Provincial General Hospital, Mombasa, Kenya.
Received 2 March, 2007
Revised 30 April, 2007
Accepted 9 May, 2007
Correspondence to Jared M. Baeten, Seattle HIV Prevention Trials Unit, University of Washington, 901 Boren Ave, Suite 1300, Seattle, WA 98104, USA. E-mail: email@example.com