Performance of the HerpeSelect (Focus) and Kalon enzyme-linked immunosorbent assays for detection of antibodies against herpes simplex virus type 2 by use of monoclonal antibody-blocking enzyme immunoassay and clinicovirological reference standards in Brazil

Twenty years of herpes simplex virus type 2 (HSV-2) research in low-income and middle-income countries: systematic evaluation of progress made in addressing WHO prioritiesfor research in HSV-2 epidemiology and diagnostics

INTRODUCTION

Low-income and middle-income countries (LMICs) have a high burden of herpes simplex virus type 2 (HSV-2) infection, which has been strongly associated with HIV. In 2001, the WHO hosted a workshop to set research priorities for HSV-2 in LMICs. Periodic re-evaluation of research priorities is essential to ensure effective allocation of resources. This study describes the progress made between 2000 and 2020 in addressing the priorities identified in two of the five thematic areas that were the workshop's focus: HSV-2 epidemiology and diagnostics. The remaining areas are addressed in a companion paper.

METHODS

A systematic search of MEDLINE, CINAHL, Global Health and Cochrane databases was carried out. Relevant primary and secondary research studies conducted in LMICs, written in English and published from 2000-2020 were included. Two independent researchers screened, identified papers and extracted preidentified variables from study texts. Data were organised into an Excel spreadsheet and analysed using IBM SPSS V.26.

RESULTS

Overall, 4445 discrete papers were identified, of which 165 publications were eligible for inclusion. The highest general population HSV-2 prevalence was reported in South and West Africa. Prevalence was higher among women than men and increased with age. HSV-2 prevalence studies among key populations were few, and the majority were in East and South Asia. Cohort studies of HSV-2 incidence among younger populations (mean age=25 years) and HSV-2 infection prevalence in North Africa and the Middle East were few. The most researched topic in HSV-2 diagnostics addressed serological techniques and direct molecular biology. Studies of point-of-care testing were also few.

CONCLUSION

HSV-2 research identified in LMICs has mainly addressed the epidemiology and diagnostics priorities identified by the 2001 WHO workshop. Unaddressed priorities include point-of-care testing, antiviral resistance and exploration of HSV-2 epidemiology in neglected geographical settings and population subgroups.

2017 European guidelines for the management of genital herpes

Genital herpes is one of the commonest sexually transmitted infections worldwide. Using the best available evidence, this guideline recommends strategies for diagnosis, management, and follow-up of the condition as well as for minimising transmission. Early recognition and initiation of therapy is key and may reduce the duration of illness or avoid hospitalisation with complications, including urinary retention, meningism, or severe systemic illness. The guideline covers a range of common clinical scenarios, such as recurrent genital herpes, infection during pregnancy, and co-infection with human immunodeficiency virus.

Prevalence and incidence estimation of HSV-2 by two IgG ELISA methods among South African women at high risk of HIV

Introduction

Previous comparison studies of the Kalon and HerpeSelect 2 ELISA IgG assays on sub-Saharan samples have found differences in the sensitivity and specificity of these assays. Using longitudinal samples from an HIV prevention study, we compared both assays and determined the HSV-2 prevalence and incidence in a South African young female population at elevated risk of acquiring HIV.

Methods

Samples at baseline were tested in both assays using the manufacturers’ guidelines (cut-off > 1.10). When non-reactive in one assay, the final visit samples were tested to determine the incidence rate. Using correlation and regression analyses, the intra- and inter-assay variabilities were assessed.

Results

The prevalence rate was 41.1% and 44.9% for Kalon and HerpeSelect using the manufacturer guidelines, respectively. Agreement between the two tests were high (kappa = 0.92). The original optical density values of both assays were highly correlated (R = 0.94), but the calibrator and correspondingly cut-off index values differed between the assays. Lowering the index value cut-off for the Kalon assay by 40% (to 0.66) resulted in a HSV-2 prevalence of 43.2%, and increased agreement between the assays (to kappa = 0.96). The incidence rate was 16.3/100 Person Years using the lower cut-off for the Kalon assay.

Discussion

In this longitudinal study, we showed that the performance of the two assays was very similar. After lowering the cut-off for the Kalon assay to 0.66 early infections were detected without impairing its specificity. The prevalence and incidence rates are in line with previously described rates for sub-Saharan African cohorts.

Population and dyadic-based seroincidence of herpes simplex virus-2 and syphilis in southern India

Objectives

Herpes simplex virus-2 (HSV-2) and syphilis are associated with increased risk of HIV, highlighting the importance of understanding their transmission dynamics. In India, most studies of HSV-2 and syphilis incidence are in high-risk populations and may not accurately reflect infectious activity. In this study, we aim to define HSV-2/syphilis incidence and risk factors in a population sample.

Methods

We conducted a longitudinal population-based survey in Andhra Pradesh, India, in two rounds: 2004–2005 and 2010–2011. Sociodemographic and behavioural data were collected, and dried blood spots tested for HSV-2 and Treponema pallidum IgG. After calculating sexually transmitted infection (STI) incidence, associated factors were assessed using modified Poisson regression and within-couple transmission rates modelled using seroconcordance/discordance data.

Results

12 617 adults participated at baseline with 8494 at follow-up. Incidence of HSV-2 and syphilis per 1000 person-years was 25.6 (95% CI 24.1 to 27.2) and 3.00 (95% CI 2.52 to 3.54). Incidence of HSV-2 was higher in women vs men (31.1 vs 20.2) and in rural vs urban residents (31.1 vs 19.0) (p<0.05 for both). STI seroincidence increased in a step-wise fashion with age and was associated with spousal seropositivity for both sexes (incidence rate ratio (IRR) 2.59 to 6.78). Within couples the rate of transmission per 1000 couple-years from men to women vs women to men was higher for HSV-2 (193.3 vs 119.0) compared with syphilis (27.6 vs 198.8), p<0.05 for both.

Conclusions

HSV-2 has higher incidence among subpopulations such as women, rural residents and older-aged individuals, suggesting a need for more generalised STI prevention approaches among populations traditionally considered low risk.

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.

Evaluation of the HerpeSelect Express rapid test in the detection of herpes simplex virus type 2 antibodies in patients with genital ulcer disease

BACKGROUND

A rapid point-of-care test with high sensitivity and specificity is required in order to fulfill the need for early detection and screening of Herpes simplex virus type 2 (HSV-2) infection among patients with genital ulcer disease (GUD), for better management and control of virus transmission.

METHODS

The goal of this study is to evaluate the performance of the commercially available HerpeSelect Express rapid test in comparison with three ELISA assays: HerpeSelect ELISA, Kalon HSV-2 glycoprotein G2 assay, and monoclonal antibody blocking enzyme immunoassay, which was used as the gold standard for the detection of HSV-2 antibodies.

RESULTS

This study showed high sensitivity (ranging from 82.6 to 100%) and specificity (100%) of the HerpeSelect Express rapid test when compared to the three ELISA assays. The agreement between the HerpeSelect Express rapid test with the three ELISAs ranged from 93.3 to 100%.

CONCLUSION

The HerpeSelect Express rapid test has adequate sensitivity and specificity for confirming HSV-2 infection in patients with GUD, indicating its suitability for epidemiological studies.

Comparative performance of the Kalon and HerpeSelect enzyme-linked immunosorbant assays to determine the prevalence of herpes simplex virus type 2 in Papua New Guinea

Background Infection with herpes simplex virus type 2 (HSV-2) is common worldwide and an important risk factor for HIV infection. Aetiological diagnosis of HSV-2 is typically determined with the use of commercially available type-specific enzyme-linked immunosorbent assays (ELISAs). This study aimed to determine the prevalence of HSV-2 among people attending sexual health clinics in the Highlands of Papua New Guinea. The study also aimed to compare the performance of two type-specific ELISA assays, the Kalon and HerpeSelect glycoprotein G2 assays, in this context.

METHODS

Participants were recruited as part of a longitudinal sexual health study. Participants attended four appointments over a 12-month period and had blood taken for HSV-2 serology at each time point. Both the Kalon and HerpeSelect assays were performed as per manufacturer's instructions.

RESULTS

A total of 132 participants were tested for HSV-2 using the Kalon and HerpeSelect ELISAs. HSV-2 prevalence was 52% (95% CI, 43-60) and 61% (95% CI, 52-69) with Kalon and HerpeSelect assays respectively. There was high concordance (87%, ?=0.75, P<0.001, n=115) between the two assays at the manufacturer recommended index value cut-offs. For participants with discordant results at baseline, (n=16), three sero-conversions were observed over the 12-month period when sequential sera was tested.

CONCLUSIONS

A high HSV-2 prevalence was observed in this clinic-based population. Our longitudinal data indicate the higher prevalence of HSV-2 detected with the HerpeSelect ELISA was likely due to false positives rather than a higher sensitivity in the early stages of infection.

European guideline for the management of genital herpes, 2010

This is the guideline for genital herpes simplex virus (HSV) management for the IUSTI/WHO Europe, 2010. They describe the epidemiology, diagnosis, clinical features, treatment and prevention of genital HSV infection. They include details on the management of HSV in pregnancy, those who are immunocompromised and the clinical investigation and management of suspected HSV-resistant disease.

Performance of the BioPlex 2200 multiplexing immunoassay platform for the detection of herpes simplex virus type 2 specific antibodies in African settings

The BioPlex platform was evaluated for the detection of herpes simplex virus 2 (HSV-2) antibodies in sub-Saharan Africa individuals in comparison to clinicovirological standards and compared to HerpeSelect. The sensitivities and specificities were, respectively, 88.9% and 93.5% for BioPlex and 89.9% and 92.7% for HerpeSelect. The agreement between both assays was 95.7%.

Performance of commercial herpes simplex virus type-2 antibody tests using serum samples from Sub-Saharan Africa: a systematic review and meta-analysis

BACKGROUND

Several commercial type-specific serologic tests are available for herpes simplex virus type 2 (HSV-2). Poor specificity of some tests has been reported on samples from sub-Saharan Africa.

METHODS

To summarize the performance of the tests using samples from sub-Saharan Africa, we conducted a systematic review of publications reporting performance of commercially available HSV-2 tests against a gold standard (Western Blot or monoclonal antibody-blocking EIA). We used random-effects meta-analyses to summarize sensitivity and specificity of the 2 most commonly evaluated tests, Kalon gG2 enzyme-linked immunosorbent assay (ELISA), and Focus HerpeSelect HSV-2 ELISA.

RESULTS

We identified 10 eligible articles that included 21 studies of the performance of Focus, and 12 of Kalon. The primary analyses included studies using the manufacturers' cut-offs (index value = 1.1). Focus had high sensitivity (random effects summary estimate 99%, 95% confidence interval [CI]: 99%-100%) but low specificity (69%, 95% CI: 59%-80%). Kalon had sensitivity of 95% (95% CI: 93%-97%) and specificity of 91% (95% CI: 86%-95%). Specificity of Focus was significantly lower (P = 0.002) among HIV-positive (54%, 95% CI: 40%-68%) than HIV-negative individuals (69%, 95% CI: 56%-82%). When the cut-off optical density index was increased above the recommended value of 1.1 to between 2.2 and 3.5, the specificity of Focus increased to 85% (95% CI: 77%-92%).

CONCLUSIONS

Sensitivity and specificity of HSV-2 tests used in sub-Saharan Africa vary by setting, and are lower than reported from studies in the United States and Europe. Increasing the cut-off optical density index may improve test performance. Evaluation of test performance in a given setting may help deciding which test is most appropriate.

Population-based seroprevalence of HSV-2 and syphilis in Andhra Pradesh state of India

BACKGROUND

Understanding the prevalence and risk factors for common causes of ulcerative genital disease in the general population would inform current STI syndromic management and HIV testing strategies in high HIV prevalence regions of India.

METHODS

Persons 15-49 years old from 32 rural and 34 urban clusters were sampled using a stratified random method to represent adults in the high HIV prevalence Guntur district in Andhra Pradesh state. Interviews were conducted and dry blood spots were collected on 12,617 study participants. Testing for HSV-2 and syphilis was performed.

RESULTS

Adjusted HSV-2 and syphilis seroprevalence rates were 4.70% and 2.08% for men and 7.07% and 1.42% for women. For men, tattooing, >3 lifetime sex partners, tobacco use, and sex with men in the past 6 months were associated with HSV-2 or syphilis (ORs, 1.66-2.95, p < 0.05). Male circumcision was positively associated with HSV-2 infection (OR, 1.37, p = 0.028) though this could be due to residual confounding. In women, greater than one lifetime partner remained significantly associated with HSV-2 in multivariate analysis (OR, 2.61; 95% CI, 1.39-4.87). Among all behavioral risk factors and other covariates in women and men, HIV infection exhibited the strongest association with HSV-2 and syphilis (ORs, 8.2-14.2, p < 0.001). The proportion of individuals with HSV-2 who were HIV infected was less than the proportion with syphilis who were HIV infected (11.8% vs. 22.7%; p = 0.001).

CONCLUSIONS

Nearly one in four persons surveyed in this population-based study that were seroprevalent for syphilis, were also HIV infected. Common population risk factors for syphilis, HSV-2 and HIV and high rates of co-seroprevalence suggest that HIV testing, STI testing and service strategies for these would benefit from direct linkage in India.

Seroprevalence of Kaposi sarcoma-associated herpesvirus and other serologic markers in the Brazilian Amazon

To determine the presence of Kaposi sarcoma–associated herpesvirus (KSHV) and other serologic markers, we tested serum specimens of 339 Amerindians, 181 rural non-Amerindians, and 1,133 urban blood donors (13 Amerindians) in the Brazilian Amazon. High KSHV seroprevalence in children and inverse association with herpes simplex virus type 2 indicates predominant nonsexual transmission among Amerindians.

Comparison of a multiplexed herpes simplex virus type-specific immunoglobulin G serology assay to immunoblot, Western blot, and enzyme-linked immunosorbent assays

The human herpes simplex virus (HSV) is highly pathogenic, with infections caused by two distinct antigenic types, HSV-1 and HSV-2. Differentiation of antibodies to these specific antigens can provide useful information for the diagnosis of subclinical or undiagnosed HSV-2 infections, as well as for reducing the risk of maternal transfer of HSV to the neonate. In this study, a multiplex assay capable of concurrent detection of HSV-1 and -2 immunoglobulin G (IgG) antibodies was compared to immunoblot, Western blot, and enzyme-linked immunosorbent assays. Agreement of the multiplex assay was 95% or greater (n = 332) for both HSV-1 and -2 compared to the three assays. Sensitivities for HSV-1 ranged from 94.9 to 97.9%, with specificities of 93 to 97%. For HSV-2, the sensitivity and specificity ranges were 92.6 to 98.9% and 98.3 to 98.7%, respectively. Our studies show that the multiplexed microsphere-based assay offers a sensitive and specific alternative method for the detection HSV-1 and -2 type-specific antibodies. Advantages of the multiplex assay include multiple results per assay, the inclusion of internal controls for each specimen, and higher throughput of results.

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.

Performance of HerpeSelect and Kalon assays in detection of antibodies to herpes simplex virus type 2

The performances of commercial enzyme-linked immunosorbent assays (ELISAs) in detecting herpes simplex virus type 2 (HSV-2) antibodies have been inconsistent for African and human immunodeficiency virus (HIV)-positive populations. We compared the performances of the HerpeSelect and Kalon glycoprotein G2 ELISAs for patients with genital ulcer disease in Ghana and the Central African Republic. Sera from 434 women were tested with the HerpeSelect assay, and a subsample (n = 199) was tested by the Kalon assay. Ulcer swabs and cervicovaginal lavage samples were tested for HSV-2 DNA by PCR. HSV-2-seronegative women with detectable genital HSV-2 DNA were retested for HSV-2 antibodies 14 and 28 days later by the two ELISAs. A total of 346 (80%) women were positive by HerpeSelect at baseline, and 225 (54%) had detectable genital (lesional or cervicovaginal) HSV-2 DNA. Sixty-six (19%) HerpeSelect-positive samples had low-positive index values (1.1 to 3.5), and 58% of these samples had detectable genital HSV-2 DNA. Global agreement between the two serological assays was 86%. Concordance was high (99%) for sera that were negative by HerpeSelect or had high index values (>3.5). Defining infection detected by HSV-2 DNA PCR and/or Kalon assay as true infection, 71% of sera with low-positive index values were associated with true HSV-2 infection. Twenty-five women were identified as having nonprimary first-episode genital HSV-2 infection. Rates of HSV-2 seroconversion at day 14 were 77% (10/13 patients) by HerpeSelect assay and 23% (3/13 patients) by Kalon assay, with four additional seroconversions detected by Kalon assay at day 28. HIV serostatus did not influence assay performance. Low index values obtained with the HerpeSelect assay may correspond to true HSV-2 infection, in particular to nonprimary first episodes of genital HSV-2 infection, and need to be interpreted in the context of clinical history.

Human herpesvirus-8 infection and oral shedding in Amerindian and non-Amerindian populations in the Brazilian Amazon region

BACKGROUND

Human herpesvirus type 8 (HHV-8) is hyperendemic in Amerindian populations, but its modes of transmission are unknown.

METHODS

Antibodies against either HHV-8 lytic antigen or HHV-8 latency-associated nuclear antigen (LANA) were detected, by immunofluorescence assays, in 339 Amerindians and 181 non-Amerindians from the Brazilian Amazon. Serological markers of oro-fecal (hepatitis A), parenteral (hepatitis B and C), and sexual (herpes simplex virus type 2 and syphilis) transmission were measured by specific ELISAs. Salivary HHV-8 DNA was detected by use of a nested polymerase chain reaction assay and was sequenced.

RESULTS

Antibodies against either lytic antigen or LANA were detected in 79.1% of Amerindians and in 6.1% of non-Amerindians (adjusted seroprevalence ratio [SR], 12.63 [95% confidence interval {CI}, 7.1-22.4]; P<.0001). HHV-8 seroprevalence increased with age among Amerindians (P(Trend) < .001) and already had high prevalence in childhood but was not sex specific in either population. The 2 populations did not differ in seroprevalence of oro-fecal or parenteral markers, but seroprevalence of markers of sexual transmission was lower among Amerindians. HHV-8 DNA in saliva was detected in 47 (23.7%) of 198 HHV-8 seropositive Amerindians. Detection of HHV-8 DNA decreased with age (P(Trend) < .04) and was more common in men (SR, 2.14 [95% CI, 1.3-3.5]; P=.003). A total of 36 (76.6%) of the 47 saliva HHV-8 DNA samples were sequenced, and all clustered as subtype E.

CONCLUSION

The data support the hypothesis of early acquisition and horizontal transmission, via saliva, of HHV-8 subtype E in Amerindian populations.