Performance of focus ELISA tests for HSV-1 and HSV-2 antibodies among university students with no history of genital herpes

Diagnosis of Herpes Simplex Virus: Laboratory and Point-of-Care Techniques

Herpes is a widespread viral infection caused by the herpes simplex virus (HSV) that has no permanent cure to date. There are two subtypes, HSV-1 and HSV-2, that are known to cause a variety of symptoms, ranging from acute to chronic. HSV is highly contagious and can be transmitted via any type of physical contact. Additionally, viral shedding can also happen from asymptomatic infections. Thus, early and accurate detection of HSV is needed to prevent the transmission of this infection. Herpes can be diagnosed in two ways, by either detecting the presence of the virus in lesions or the antibodies in the blood. Different detection techniques are available based on both laboratory and point of care (POC) devices. Laboratory techniques include different biochemical assays, microscopy, and nucleic acid amplification. In contrast, POC techniques include microfluidics-based tests that enable on-spot testing. Here, we aim to review the different diagnostic techniques, both laboratory-based and POC, their limits of detection, sensitivity, and specificity, as well as their advantages and disadvantages.

Performance of four diagnostic assays for detecting herpes simplex virus type 2 antibodies in the Middle East and North Africa

BACKGROUND

Assessments of commercial assays in detecting herpes simplex virus type 2 (HSV-2) antibodies have shown variable sensitivity and specificity, and variation in performance by global population.

OBJECTIVE

To evaluate performance of four assays in detecting HSV-2 antibodies in a composite Middle Eastern and North African (MENA) population. The assays are two ELISA kits: HerpeSelect^® 2 ELISA IgG and Euroimmun Anti-HSV-2 (gG2) ELISA (IgG), and two immunoblot (IB)/Western blot (WB) assays: HerpeSelect^® 1 and 2 Immunoblot IgG and Euroimmun Anti-HSV-1/HSV-2 gG2 Euroline-WB (IgG/IgM).

STUDY DESIGN

Blood specimens were drawn from blood donors between 2013-2016 in Doha, Qatar. Twenty specimens from ten nationalities (Egypt, Iran, Jordan, Lebanon, Pakistan, Palestine, Qatar, Sudan, Syria, and Yemen; total = 200) were randomly selected and tested for HSV-2 antibodies.

RESULTS

In the six possible assay comparisons, Cohen's kappa statistics indicated fair to good agreement, ranging between 0.57 (95% CI 0.28-0.86) and 0.69 (95% CI 0.44-0.95). Meanwhile, positive percent agreement ranged between 50.0 (95% CI 18.7-81.3%) and 63.6% (95% CI 30.8-89.1%); negative percent agreement ranged between 97.8% (95% CI 94.4-99.4%) and 99.5% (95% CI 97.0-100.0%); and overall percent agreement ranged between 95.8% (95% CI 91.9-97.9%) and 97.5% (95% CI 94.2-98.9%). The two ELISA kits demonstrated comparable sensitivities and specificities ≥50% and >98%, respectively, with respect to the IB/WB assays.

CONCLUSION

The study provided, for the first time, primary data on performance of these assays in diagnosing HSV-2 infection in MENA populations. Findings support comparable performance and utility of these assays, and demonstrate challenges in establishing seropositivity (versus seronegativity).

Performance of Commercial Enzyme-Linked Immunoassays for Diagnosis of Herpes Simplex Virus-1 and Herpes Simplex Virus-2 Infection in a Clinical Setting

BACKGROUND

US Food and Drug Administration-approved enzyme-linked immunoassays (EIA) for determining type-specific herpes simplex virus (HSV) serostatus are widely used in clinical practice. We compared the performance of such assays with the University of Washington Western blot (UW WB) in patients who sought confirmation of their HSV serology result.

METHODS

We reviewed charts of all persons evaluated at the Westover Heights Clinic in Portland, Oregon, from July 2010 through September 2015, who had a HSV EIA, followed by UW WB.

RESULTS

Of 864 persons, 47% were women. The median age was 36 years (range, 18-73 years). Using UW WB to define infection status, 286 (33%) persons were HSV-1 seropositive only, 104 (12%) were HSV-2 seropositive only, 134 (16%) were both HSV-1 and HSV-2 seropositive, 235 (27%) were HSV seronegative, and 105 (12%) had indeterminate results. Compared with the UW WB as the criterion standard, EIA was 70.2% sensitive and 91.6% specific for HSV-1, and 91.9% sensitive and 57.4% specific for HSV-2.Among 278 persons who were HSV-1 seropositive by EIA, 255 were confirmed by the UW WB (positive predictive value [PPV], 91.7%). Of the 360 persons that were HSV-1 seronegative by the EIA, 252 were seronegative by UW WB (negative predictive value [NPV], 70.0%). Among 381 persons with HSV-2 EIA seropositivity, 193 tested HSV-2 seropositive by the UW WB (PPV, 50.7%). Of the 270 persons HSV-2 seronegative by EIA, 17 were seropositive with the UW WB (NPV, 93.7%). Among 261 persons with an EIA HSV-2 index value = 1.1-2.9, 39.8% of results were confirmed by UW WB, compared with 78.6% of the 70 persons with an EIA index value of 3 or greater (P < 0.001). The risk of false-positive HSV-2 EIA results was higher in those with HSV-1 antibody (47.1% vs 37.1%, P = 0.036).

CONCLUSIONS

US Food and Drug Administration-approved EIAs have poor PPV for HSV-2 and poor NPV for HSV-1 in clinical practice. More accurate rapid type-specific HSV antibody tests are needed.

Prevalent Herpes Simplex Virus-2 Increases the Risk of Incident Bacterial Vaginosis in Women from South Africa

Studies have shown that women diagnosed with herpes simplex virus-2 (HSV-2) have a higher risk for bacterial vaginosis (BV) infection. We investigated the presence of HSV-2 infections as a risk factor for incident BV infections in high risk, Human immunodeficiency virus (HIV) uninfected women enrolled in a HIV prevention trial in Durban, South Africa. The Vaginal and Oral Interventions to Control the Epidemic trial was a multicentre, double blinded, randomized controlled trial which was designed to estimate the effectiveness of daily treatment with vaginal tenofovir gel, oral tenofovir disoproxil fumarate and oral Truvada in preventing HIV-1 infection in women. Women provided samples for the diagnosis of HSV-2 and BV. The presence of HSV-2 antibodies was detected using HerpeSelect™ ELISA IgG. Bacterial vaginosis was diagnosed using the Nugent scoring system. To assess the risk of BV incidence, modelled as a time-dependent variable, we used the Andersen-Gill model with robust variance estimation and Efron methods for ties. Overall, 2750 women were enrolled in the VOICE trial at our study sites. Women who had a HSV-2 infection at enrolment were shown to be at increased risk for incident BV infections (adjusted hazard ratio 1.17, 95% CI 1.08, 1.27, p ≤ 0.001). In addition, being of a young age, being unmarried and having a partner that has other partners were significantly associated with subsequent BV infection. Our findings therefore advocate the need for strengthening STI prevention efforts among women in high burden STI settings.

Performance evaluation of four type-specific commercial assays for detection of herpes simplex virus type 1 antibodies in a Middle East and North Africa population

BACKGROUND

The number of diagnostic assays for the detection of herpes simplex virus type 1 (HSV-1) antibodies has increased over the years. However, their performance characteristics could vary among global populations.

OBJECTIVE

To investigate performance of two commercial ELISA kits, HerpeSelect^® 1 ELISA and Euroimmun Anti-HSV-1 (gC1) ELISA (IgG); and two commercial immunoblot (IB)/Western blot (WB) assays, HerpeSelect^® 1 and 2 Immunoblot IgG, and Euroimmun Anti-HSV-1/HSV-2 gG2 Euroline-WB (IgG/IgM); in detecting HSV-1 antibodies in a Middle East and North Africa (MENA) population.

STUDY DESIGN

Blood specimens were collected from blood donors in Doha, Qatar, June 2013-2016. Twenty specimens were randomly selected from 10 MENA nationalities (Egypt, Iran, Jordan, Lebanon, Pakistan, Palestine, Qatar, Sudan, Syria, and Yemen; total = 200), and tested for HSV-1 antibodies.

RESULTS

Across all six comparisons between assays, positive percent agreement ranged between 95.7% (95% CI: 91.4-98.3%) and 100.0% (95% CI: 97.8-100.0%). Negative percent agreement ranged between 86.2% (95% CI: 68.3-96.1%) and 96.2% (95% CI: 80.4-99.9%). Overall percent agreement ranged between 95.7% (95% CI: 91.7-97.8%) and 99.4% (95% CI: 96.7-99.9%). Cohen's kappa statistic ranged between 0.84 (95% CI: 0.73-0.95) and 0.98 (95% CI: 0.93-1.00). Compared against IB/WB, HerpeSelect^® and Euroimmun had sensitivities and specificities >96% and >86%, respectively. Positive and negative predictive values were >97% and >83%, respectively.

CONCLUSION

The assays showed excellent concordance with one another, and with a high kappa statistic. The ELISA kits demonstrated robust diagnostic performance compared to the IB/WB assays. These findings support the assays' utility in clinical diagnosis and research in MENA populations.

Estimating seroprevalence of herpes simplex virus type 1 among different Middle East and North African male populations residing in Qatar

HSV‐1 epidemiology in the Middle East and North Africa (MENA) remains poorly understood. Our study aimed to measure HSV‐1 antibody prevalence (seroprevalence) and its age‐distribution among select MENA populations residing in Qatar. Sera were collected from male blood donors attending Hamad Medical Corporation 2013‐2015. A total of 2,077 sera were tested for anti‐HSV‐1 antibodies using HerpeSelect^® 1 ELISA IgG kits (Focus Diagnostics, Cypress, CA). Robust Poisson regression was conducted to estimate adjusted infection prevalence ratios. Country‐specific HSV‐1 seroprevalence was estimated for 10 national populations: 97.5% among Egyptians, 92.6% among Yemenis, 90.7% among Sudanese, 88.5% among Syrians, 86.5% among Jordanians, 82.3% among Qataris, 81.4% among Iranians, 81.4% among Lebanese, 80.5% among Palestinians, and 77.0% among Pakistanis. Age‐specific HSV‐1 seroprevalence was estimated for Egypt, the Fertile Crescent (Iraq, Jordan, Lebanon, Palestine, and Syria), and Qatar. Seroprevalence increased with age among Fertile Crescent and Qatari nationals. Seroprevalence increased from 70.0% among those aged ≤ 24 years up to 98.0% among those aged ≥55 years among Fertile Crescent nationals. Seroprevalence was consistently above 90% for all ages among Egyptians. HSV‐1 seroprevalence is high in MENA, though with some variation across countries. The seroprevalence appears to have declined among current young age cohorts compared to its levels a few decades ago.

A pilot study examining the safety and tolerability of valacyclovir in veterans with hepatitis C virus/herpes simplex virus type 2 coinfection

INTRODUCTION

We performed a pilot study examining the safety and tolerability of valacyclovir in veterans with herpes simplex virus type 2 and hepatitis C virus (HCV) coinfection.

METHODS

We performed a randomized double-blind, placebo-controlled, crossover clinical trial in U.S. veterans with genotype 1 HCV/herpes simplex virus type 2 coinfection. Patients were randomized 1:1 in blocks of 10 to receive either 1 g twice-daily valacyclovir or matching placebo for 8 weeks followed by a 2-week washout phase with daily placebo. The alternate therapy (valacyclovir or placebo) was given for an additional 8-week period. Safety assessments were performed every 2 weeks. Changes in HCV RNA and alanine aminotransferase (ALT) were estimated using linear mixed models (SAS Proc Mixed).

RESULTS

Thirty patients were enrolled. Valacyclovir was not associated with toxicity or adverse events. ALT levels declined 6% to 10%; mean HCV RNA levels were reduced 24% (1.3 million IU/mL [0.21 log10 IU/mL]) during the valacyclovir phase (P = 0.08) with no carryover effect observed (P = 0.21).

CONCLUSIONS

Valacyclovir 1 g twice daily showed no evidence of hepatotoxicity in U.S. veterans with hepatitis C. A modest reduction in serum levels of ALT and plasma levels of HCV RNA was observed.

Cold sore susceptibility gene-1 genotypes affect the expression of herpes labialis in unrelated human subjects

Our group has recently described a gene on human chromosome 21, the Cold Sore Susceptibility Gene-1 (CSSG-1, also known as C21orf91), which may confer susceptibility to frequent cold sores in humans. We present here a genotype–phenotype analysis of CSSG-1 in a new, unrelated human population. Seven hundred fifty-eight human subjects were enrolled in a case/control Cold Sore Study. CSSG-1 genotyping, herpes simplex virus 1 (HSV1) serotyping, demographic and phenotypic data was available from 622 analyzed subjects. Six major alleles (H1–H6) were tested for associations with each of the self-reported phenotypes. The statistical analysis was adjusted for age, sex and ethnicity. Genotype–phenotype associations were analyzed from 388 HSV1-seropositive subjects. There were significant CSSG-1 haplotype effects on annual cold sore outbreaks (P=0.006), lifetime cold sores (P=0.012) and perceived cold sore severity (P=0.012). There were relatively consistent trends toward protection from frequent and severe cold sores among those with the H3 or H5/6 haplotypes, whereas those with H1, H2, and H4 haplotypes tended to have more frequent and more severe episodes. Different alleles of the newly described gene CSSG-1 affect the expression of cold sore phenotypes in this new, unrelated human population, confirming the findings of the previous family-based study.

Sexually transmitted and anorectal infectious diseases

Sexually transmitted diseases (STDs) are common and they can involve the anus and rectum in both men and women. In this article, the main bacterial and viral STDs that affect the anus and rectum are discussed, including their prevalence, presentation, and treatment.

The epidemiology of sexually transmitted co-infections in HIV-positive and HIV-negative African-Caribbean women in Toronto

BACKGROUND

HIV disproportionately affects African-Caribbean women in Canada but the frequency and distribution of sexually transmitted infections in this community have not been previously studied.

METHODS

We recruited women based on HIV status through a Toronto community health centre. Participants completed a socio-behavioural questionnaire using Audio Computer Assisted Self-Interview (ACASI) and provided blood for syphilis, HIV, hepatitis B and C, herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), and human cytomegalovirus (CMV) serology, urine for chlamydia and gonorrhea molecular testing and vaginal secretions for bacterial vaginosis (BV) and human papillomavirus (HPV). Differences in prevalence were assessed for statistical significance using chi-square.

RESULTS

We recruited 126 HIV-positive and 291 HIV-negative women, with a median age of 40 and 31 years, respectively (p < 0.001). Active HBV infection and lifetime exposure to HBV infection were more common in HIV-positive women (4.8% vs. 0.34%, p = 0.004; and 47.6% vs. 21.2%, p < 0.0001), as was a self-reported history of HBV vaccination (66.1% vs. 44.0%, p = 0.0001). Classical STIs were rare in both groups; BV prevalence was low and did not vary by HIV status. HSV-2 infection was markedly more frequent in HIV-positive (86.3%) than HIV-negative (46.6%) women (p < 0.0001). Vaginal HPV infection was also more common in HIV-positive than in HIV-negative women (50.8% vs. 22.6%, p < 0.0001) as was infection with high-risk oncogenic HPV types (48.4% vs. 17.3%, p < 0.0001).

CONCLUSIONS

Classical STIs were infrequent in this clinic-based population of African-Caribbean women in Toronto. However, HSV-2 prevalence was higher than that reported in previous studies in the general Canadian population and was strongly associated with HIV infection, as was infection with hepatitis B and HPV.

The Epidemiology of Herpes Simplex Virus Type-2 Infection among Pregnant Women in Rural Mysore Taluk, India

Objectives. To assess the prevalence and determinants of herpes simplex virus type 2 (HSV-2) infections among pregnant women attending mobile antenatal health clinic in rural villages in Mysore Taluk, India. Methods. Between January and September 2009, 487 women from 52 villages participated in this study. Each participant consented to provide a blood sample for HSV-2 and HIV testing and underwent an interviewer-administered questionnaire. Results. HSV-2 prevalence was 6.7% (95% confidence interval (CI) 4.4–9.0), and one woman tested positive for HIV. The median age of women was 20 years and 99% of women reported having a single lifetime sex partner. Women whose sex partner traveled away from home had 2.68 (CI: 1.13–6.34) times the odds of being HSV-2 seropositive compared to women whose sex partner did not travel. Having experienced genital lesions was also associated with HSV-2 infection (P value = 0.08). Conclusion. The 6.7% HSV-2 prevalence was similar to results obtained in studies among pregnant women in other parts of India. It appeared that most women in this study contracted HSV-2 from their spouses and few regularly used condoms. This finding highlights the need for public health policies to increase awareness and education about prevention methods among women and men living in rural India.

Light microscopy, culture, molecular, and serologic methods for detection of herpes simplex virus

Herpes simplex virus 1 (HSV-1) and 2 (HSV-2) cause a variety of human diseases, ranging from acute to chronic and mild to severe. The absence of curative therapy results in lifelong carriage marked by recurrent outbreaks and allows transmission of the virus to uninfected individuals. Nonspecific lesions, variable presentation, and chronic carriage necessitate the use of different laboratory testing methods appropriate for each presentation. A thorough understanding of the performance characteristics and limitations of available tests is critical for selection of the appropriate test and interpretation of results. Clinical sensitivity, specificity, and selection of the appropriate methodology is paramount to avoid misdiagnosis and guide therapy. In this article we review the different methods for detection and typing of HSV, including light microscopy, culture, serology, and nucleic acid-based tests. We discuss the strengths and weaknesses of each method for diagnosing HSV infection, cite performance characteristics, and review appropriate clinical uses.

Public health strategies for prevention and control of HSV-2 in persons who use drugs in the United States

BACKGROUND

Herpes simplex virus type 2 (HSV-2) affects HIV acquisition, transmission, and disease progression. Effective medications for genital herpes and for HIV/AIDS exist. Parenteral transmission of HIV among persons who inject drugs is decreasing. Reducing sexual transmission of HIV and HSV-2 among persons who use drugs (PWUD; i.e., heroin, cocaine, "speedball", crack, methamphetamine through injection or non-injection) necessitates relevant services.

METHODS

We reviewed HSV-2 sero-epidemiology and HSV-2/HIV associations in U.S.-based studies with PWUD and the general literature on HSV-2 prevention and treatment published between 1995 and 2012. We used the 6-factor Kass framework to assess relevant HSV-2 public health strategies and services in terms of their goals and effectiveness; identification of, and minimization of burdens and concerns; fair implementation; and fair balancing of benefits, burdens, and concerns.

RESULTS

Eleven studies provided HSV-2 serologic test results. High HSV-2 sero-prevalence (range across studies 38-75%) and higher sero-prevalence in HIV-infected PWUD (97-100% in females; 61-74% in males) were reported. Public health strategies for HSV-2 prevention and control in PWUD can include screening or testing; knowledge of HSV-2 status and partner disclosure; education, counseling, and psychosocial risk-reduction interventions; treatment for genital herpes; and HIV antiretroviral medications for HSV-2/HIV co-infected PWUD.

CONCLUSIONS

HSV-2 sero-prevalence is high among PWUD, necessitating research on development and implementation of science-based public health interventions for HSV-2 infection and HSV-2/HIV co-infections, including research on effectiveness and cost-effectiveness of such interventions, to inform development and implementation of services for PWUD.

The glycoproteins C and G are equivalent target antigens for the determination of herpes simplex virus type 1-specific antibodies

Seroreactivity to the glycoproteins C and G of herpes simplex virus type 1 (HSV-1) was compared in 310 serum samples using a Western blot assay containing a whole antigen extract of HSV-1 and an ELISA employing gC1 isolated from HSV-1. The prevalence of reactivity to gC1 was 75.8% by Western blot and 73.9% by ELISA, while antibody responses to gG1 were detected in 72.9% of sera by Western blot. An absolute correlation of 96.1% between the reactivity to gC1 and gG1 was demonstrated using the Western blot. The gC1-based ELISA correlated with Western blot detection of anti-gC1 and anti-gG1 antibodies in 95.2 and 97.7% of samples, respectively. 3.2% of all sera were reactive with gC1 in Western blot and/or ELISA, but were negative for anti-gG1. For analysis of cross-reactivity, antibodies against HSV-2, Epstein-Barr virus, varicella-zoster virus and cytomegalovirus were determined. The prevalence of antibodies against each individual virus was identical in the groups of sera reactive with gC1 or gG1. These findings indicate that gC1 and gG1 are equivalent antigenic targets for the type-specific serodiagnosis of HSV-1 infections.

Characteristics associated with genital herpes testing among young adults: assessing factors from two national data sets

OBJECTIVES AND PARTICIPANTS: in the United States, genital herpes (GH) prevalence is 10.6% among 20- to 29-year-olds and about 90% of seropositive persons do not know their status. This study investigated individual characteristics associated with GH screening and diagnosis in sexually active young adults aged 18 to 24.

METHODS

two data sets were analyzed: the National Longitudinal Study of Adolescent Health (Add Health) Wave III from 2001 to 2002 (n = 11,570) and the American College Health Association's (ACHA's) national survey of college students from 2000 to 2006 (n = 222,470).

RESULTS

in Add Health, 18.4% of females and 7.1% of males self-reported GH testing in the previous 12 months, compared to 0.7% for self-reported GH diagnosis in ACHA. GH testing and diagnosis was strongly positively associated with a history of human immunodeficiency virus (HIV) testing and diagnosis of sexually transmitted infections (STIs) in the previous 12 months for both sexes.

CONCLUSIONS

integrating herpes screening and testing into HIV and standard STI screening would identify more infections.

Serologic detection of herpes simplex virus type 2 antibodies among pregnant women using a point-of-care test from Focus Diagnostics

BACKGROUND

Serologic assays that identify herpes simplex type 2 (HSV-2) type-specific antibodies have been commercially available for more than a decade. Greater acceptance of these tests is hindered by uncertainty regarding their performance in real-world clinical settings.

OBJECTIVES

The primary objective was to compare the test characteristics of the Focus HerpeSelect Express Assay (EA) versus the Focus HerpeSelect enzyme linked immunoassay (ELISA) for detection of HSV-2 type-specific antibodies among pregnant women enrolled from 3 geographic sites with varying prevalences of HSV-2 infection. A second objective was to evaluate the performance of a HSV-2 testing strategy in which EA screens and ELISA confirms HSV-2 serodiagnosis.

STUDY DESIGN

We enrolled 399 pregnant women from Atlanta, GA, Moorestown, NJ, and Pittsburgh, PA into this cross-sectional investigation. Capillary whole blood was obtained from study participants, and evaluated for the presence of type-specific HSV-2 antibodies using the EA. Serum samples were also obtained from all study participants for subsequent identification of HSV-2 type-specific antibodies using both ELISA and the Focus Immunoblot assays.

RESULTS

We observed 96.2% agreement between results obtained with EA and ELISA. Overall, when compared to ELISA results, the sensitivity of EA for detection of HSV-2 type-specific antibodies was 94.2% and the specificity was 97.1%. Using Immunoblot results as our standard for performance calculations, the positive predictive value (PPV) of HSV-2 serodiagnosis increased from 91.7% to 98.2% when ELISA was used to confirm EA testing.

CONCLUSIONS

EA provides similar results to ELISA for the identification of HSV-2 type-specific antibodies among pregnant women. As use of the point-of-care (POC) EA in conjunction with confirmatory ELISA testing improves the PPV of HSV-2 serodiagnosis compared to the use of EA or ELISA testing alone, validation of this diagnostic algorithm in other at-risk populations may be warranted.

Serologic screening for herpes simplex virus among university students: a pilot study

OBJECTIVE

The authors examined the feasibility of conducting serologic testing for the herpes simplex virus 2 (HSV-2) among university students and assessed the psychosocial impact of an HSV-2 diagnosis.

METHODS

The authors recruited a convenience sample of 100 students (aged 18-39 years) without a history of genital herpes from 1 university between September 2004 and March 2006. Participants received HSV-2 antibody testing by Focus ELISA and Western Blot assays and completed a questionnaire that addressed psychological functioning. Twenty-eight participants completed the questionnaire again at a 3-month follow-up visit.

RESULTS

The study revealed (1) low test-reliability in the student population, (2) that positive test results may cause a decline in psychological well-being, and (3) that substantial resources are required to support students with positive HSV-2 results.

CONCLUSIONS

Test performance, psychological impact, and availability of resources for counseling students with positive diagnoses should be considered before implementing HSV testing programs.

Herpes simplex virus type 2 antibody detection performance in Kisumu, Kenya, using the Herpeselect ELISA, Kalon ELISA, Western blot and inhibition testing

BACKGROUND

In certain parts of Africa, type-specific herpes simplex virus type 2 (HSV-2) ELISAs may have limited specificity. To date, no study has been conducted to validate HerpeSelect and Kalon type-specific HSV-2 ELISAs using both the Western blot and recombinant gG ELISA inhibition testing as reference standards.

METHODS

A total of 120 men who were HIV seronegative (aged 18-24 years) provided blood samples. HSV-2 IgG serum antibodies were detected using four different methods: HerpeSelect HSV-2 ELISA (n = 120), Kalon HSV-2 ELISA (n = 120), University of Washington Western blot (n = 101) and a recombinant inhibition test (n = 93).

RESULTS

HSV-2 seroprevalence differed significantly by HSV-2 detection method, ranging from 24.8% with the Western blot to 69.8% with the HerpeSelect ELISA. Using the Western blot as the reference standard, the HerpesSelect had the highest sensitivity for HSV-2 antibody detection (100%) yet lowest specificity (40%). Similar results were obtained using the inhibition test as the reference standard. The sensitivity and specificity of the Kalon test versus the Western blot were 92% and 79%, respectively, and 80% and 82% versus the inhibition test. Using the inhibition test as the reference standard, the sensitivity of the Western blot appeared low (49%).

CONCLUSIONS

In men in western Kenya who were HIV seronegative, the HerpeSelect and Kalon type-specific ELISAs had high sensitivities yet limited specificities using the Western blot as reference standard. Overall, the Kalon ELISA performed better than the HerpeSelect ELISA in these young men from Kisumu. Further understanding is needed for the interpretation of HSV-2 inhibition or ELISA test positive/ Western blot seronegative results. Before HSV-2 seropositivity may be reliably reported in selected areas of Africa, performance studies of HSV-2 serological assays in individual geographical areas are recommended.