Genital Immune Correlates of Seroprevalent and Seroincident Herpes Simplex Type 2 Infection Among Women Who Sell Sex in Nairobi, Kenya

Problem Most Herpes simplex virus type 2 (HSV‐2) infection is asymptomatic but increases the risk of HIV acquisition, possibly due to alterations in genital immunology. We examine associations of HSV‐2 prevalence and incidence with epithelial barrier disruption. Method of Study The study was nested within the longitudinal Maisha Fiti cohort of women who sell sex in Nairobi, Kenya. HSV‐2 serostatus was assessed by Kalon HSV‐2 IgG assay. Socio‐behavioural characteristics were assessed by questionnaire and analysed by logistic regression. Immune factors (including soluble E‐cadherin (sE‐cad)) were assayed in cervicovaginal secretions by multiplex immunoassay, log‐transformed and analysed through linear regression. Results Among 731 HIV‐negative participants, 414 (57%) were HSV‐2 seropositive. These women were older (median age 35 vs 28 years; p < 0.001) and reported increased intravaginal washing (64 vs 56%; p = 0.027) than those who were HSV‐2 seronegative. Genital sE‐cad levels were similar, and IL‐6 levels were lower in seropositive participants (1.15 vs 1.28 pg/mL, p < 0.01). Seroincidence was 10.7/100 person (95% CI: 7.3, 15.2) years among the 317 initially seronegative participants. Incident infection was associated with older age (31 vs 28 years, p = 0.001), increased number of clients (6 vs 4 clients/week, p = 0.005), and bacterial vaginosis (BV) (32 vs 15%, p = 0.009). Although women who acquired HSV‐2 had higher sE‐cad and lower MIP‐3 α levels, there was no association after controlling for Nugent score. Conclusions Subclinical epithelial barrier disruption is unlikely to be underpinning HIV acquisition in asymptomatic HSV‐2 infection. There was no evidence of genital immune predictors of HSV‐2 acquisition, whereas the vaginal microbiome is important.