Objectives: Several studies have demonstrated an association between herpes simplex virus type 2 (HSV-2) and HIV-1, but available data on risk factors for HSV-2 acquisition are limited. The objective of this analysis was to determine the incidence and risk factors for HSV-2 acquisition among HIV-1-seronegative female sex workers in Kenya.
Methods: Between February 1993 and December 2006, HIV-1-seronegative women attending a municipal sexually transmitted infection (STI) clinic were invited to enroll in a prospective cohort study. Screening for HIV-1 and STIs were done at monthly follow-up visits. Archived blood samples were tested for HSV-2.
Results: Of 1527 HIV-1-seronegative women enrolled, 302 (20%) were HSV-2 seronegative at baseline of whom 297 had at least one follow-up visit. HSV-2 incidence was high (23 cases/100 person-years; 115 cases). In multivariate analysis, HSV-2 was significantly associated with more recent entry into sex work, workplace and higher number of sex partners per week. Condom use was protective, although this was statistically significant only for the intermediate strata (25–75% condom use; HR 0.43; p = 0.05). There were statistical trends for bacterial vaginosis to increase HSV-2 risk (HR 1.56; p = 0.07) and for oral contraceptive use to decrease risk (HR 0.50; p = 0.08). The 23% annual HSV-2 incidence in this study is among the highest reported anywhere in the world.
Conclusions: Women were at increased risk if they had recently entered sex work, had a higher number of sex partners or worked in bars. HSV-2 risk reduction interventions are urgently needed among high-risk African women.
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Funding This study was supported by a grant from the Fred Hutchinson Cancer Research Centre (NCI P30 CA015704) and by the US National Institutes of Health (R37 AI38518).
Competing interests None.
Ethics approval The ethical review boards at the University of Washington, Kenyatta National Hospital and the Fred Hutchinson Cancer Research Center approved the study.
Contributors: VC is the corresponding author, conducted/oversaw all laboratory testing of HSV-2 and other STIs for the study and led the drafting of the manuscript. JB contributed to the study design, data analysis, drafting of the manuscript and approved the final draft. SB established the HSV-2 testing in Mombasa, contributed to drafting of the manuscript and approved the final draft. SG and LL oversaw and contributed to collection of the clinical data and samples for the study, drafting of the manuscript and approved the final draft. KM supervised laboratory work and quality assurance for the study, contributed to drafting of the manuscript and approved the final draft. JON-A contributed to the establishment of the cohort, including development of the core clinical and laboratory procedures, helped to oversee both clinical work and laboratory procedures for the current study, contributed to drafting of the manuscript and approved the final draft. WJ contributed to the study design and provided oversight for both the clinical and laboratory aspects of the study, contributed to drafting of the manuscript and approved the final draft. JO contributed to the establishment of the cohort and the design of the current study, secured the funding for HSV testing in the cohort, contributed to drafting of the manuscript and approved the final draft. RSM contributed to the design and core procedures of the cohort, helped to develop the design of the current study and interpretation of the findings, and oversaw manuscript preparation and approved the final draft.
Provenance and Peer review Commissioned; externally peer reviewed.
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