P5.072 The Performance of Two IgG ELISA Methods to Detect HSV-2 Infections Among South-African Women Who Are at Higher Risk of Becoming HIV Infected

Abstract

Background HSV infections during pregnancy are generally asymptomatic and associated with high rate of neonatal morbidity and death. Differential serologic diagnosis of HSV infections in pregnancy is important for the correct assessment of the infection status. The aim of this study was to evaluate the performance of Roche Elecsys ® assays for the type specific determination of HSV-1 and HSV-2 IgG antibodies. Methods A total of 800 samples obtained from sexually active adults (n = 300), pregnant women (n = 400) and herpes infection suspected patients(n = 100) were analysed using Roche Elecsys ® HSV-1 and HSV-2 assays and commercially available Focus Diagnostics HerpeSelect, Radim HERPES S.V and Diasorin LIAISON type specific ELISA assays.A commercially available Western Blot assay was used for the resolution of the discrepant results.For further confirmation of the type specific detection performance of the Elecsys ® HSV-1 and HSV-2 assays 310 potentially cross reactive samples for HSV-2 and 123 samples for HSV-1 were analysed. Results The Elecsys ® HSV-1 IgG assay showed a relative sensitivity of 95.6 to 100%. The relative specificity was between 97.6 and 100%. The Elecsys ® HSV-2 IgG assay showed a relative sensitivity of 92.6 to 100%. The relative specificity was between 98.7 and 100%. These assays exhibits excellent differentiation between HSV-1 and HSV-2 infections with no cross reactivity to other herpes viruses like CMV, VZV or EBV. Conclusion The results obtained with the type specific Roche Elecsys ® HSV-1 and HSV-2 assays indicate that these assays are useful, specific and sensitive for the differential determination of HSV-1 and HSV-2 IgG antibodies in serum or plasma samples. The advantage of the Roche Elecsys ® assays compared to ELISA based assays, is that these assays are rapid and can be performed in a fully automated process. Background Specimens collected in Pretoria for the FEM-PrEP study, a phase III trial on pre-exposure prophylaxis for HIV prevention among African women, were tested for Herpes Simplex Virus type II (HSV-2). We present here the performance of the Focus HerpeSelect and Kalon HSV-2 gG2 ELISA. Methods The HSV-2 infection was determined in 701 women at baseline with two IgG ELISAs: Kalon HSV-2 gG2 ELISA (Kalon Biologicals Ltd.) and HerpeSelect HSV IgG ELISA (Focus Technologies). Participants were considered true positive for HSV-2 when specimens were reactive in both assays. In order to determine incident HSV-2 infections during the study, specimens collected at final visit (i.e. after 52 weeks/at product interruption visit) of participants being HSV-2 seronegative at baseline were tested using the same assays. Results At baseline, 287 and 315 positive results were found using the Kalon-and Focus assay, respectively. All Kalon positives were also positive in the Focus assay and considered to be true infections (initial prevalence: 40.9%). Of the 28 specimens positive with the Focus only, 10 of them became true positive at final visit. We therefore assume that the Kalon missed 10...