Ability of a rapid serology test to detect seroconversion to herpes simplex virus type 2 glycoprotein G soon after infection

Herpes simplex virus-2 infections in pregnant women from South Africa: Evaluation of the ImmunoFLOW rapid test

The diagnostic performance of ImmunoFLOW, a rapid test for detecting herpes simplex virus type-2 (HSV-2) infections, was investigated in 248 antenatal women. Approximately one hundred and seventy-seven (71%) of the enrolled women were infected with HSV-2. Sero-positivity was associated with older age ([≥ 30 years] 104/177, 58%), having a secondary level of education but not tertiary level of education (125/177, 70.6%), and being unmarried (150/177, 84.7%). The sensitivity of the ImmunoFLOW test in relation to the HerpeSelect HSV-2 enzyme-linked immunosorbent assay was 89.7% and specificity was 96.2%. The ImmunoFLOW therefore can serve as a valuable test in screening for HSV-2 infections in pregnant women.

[Management of pregnant women with first episode of genital herpes. Guidelines for clinical practice from the French college of gynecologists and obstetricians (CNGOF)]

OBJECTIVE

To provide guidelines for the management of first episode genital herpes during pregnancy and in the immediate postpartum period.

METHODS

MedLine and Cochrane Library databases search and review of the main foreign guidelines.

RESULTS

In case of first episode genital herpes during pregnancy, antiviral treatment with acyclovir (200mg 5 times daily) or valacyclovir (1000mg twice daily) for 5 to 10 days is recommended (grade C). The patient should be tested for HIV if not previously done (grade B). Daily suppressive antiviral treatment with acyclovir (400mg 3 times daily) or valacyclovir (500mg twice daily) is recommended from 36 weeks for women who have had a first episode genital herpes during pregnancy (grade B). A cesarean section should be performed in case of suspicion of first episode genital herpes at the onset of labor (grade B) or premature rupture of the membranes at term (professional consensus), or in case of first episode genital herpes less than 6 weeks before delivery (professional consensus). In the event of first episode genital herpes highlighted in the postpartum period, the neonatologist should be informed (professional consensus). The patient may be treated according the scheme described above.

CONCLUSION

A cesarean section should be performed in case of first episode genital herpes less than 6 weeks before delivery.

Comparison of commercial methods of immunoblot, ELISA, and chemiluminescent immunoassay for detecting type-specific herpes simplex viruses-1 and -2 IgG

BACKGROUND

Serology for type-specific herpes simplex virus (HSV) is based on the use of the respective glycoprotein G (gG).

METHODS

Chemiluminescent immunoassay (CLIA; BIO-FLASH^® , Biokit, Spain), ELISA (HerpeSelect^® , Focus, USA), and immunoblot (IB; Virotech, Germany) for detecting HSV-1- and HSV-2-specific IgG were compared using 384 serum samples received for HSV serology. The samples were classified as positive or negative according to a consensus criterion.

RESULTS

For HSV-1, 262 samples were positive and 118 were negative (four samples were unclassifiable). IB showed agreement, sensitivity, and specificity values of 98.68%, 98.47% and 99.15%, respectively. The corresponding figures for CLIA and ELISA were 98.95%, 99.24% and 98.31%, and 98.16%, 99.62% and 94.92%, respectively. For HSV-2, 106 samples were positive and 278 were negative. Agreement, sensitivity, and specificity of IB were 99.48%, 98.11%, and 100%, respectively. The corresponding figures for CLIA and ELISA were 99.48%, 99.06% and 99.64%, and 98.18%, 99.06% and 97.84%, respectively.

CONCLUSION

The three methods showed excellent and equivalent performance characteristics for the detection of type-specific IgG to HSV-1 and HSV-2.

First estimates of the global and regional incidence of neonatal herpes infection

Background

Neonatal herpes is a rare but potentially devastating condition (60% fatality without treatment). Transmission usually occurs during delivery from mothers with herpes simplex virus type 1 (HSV-1) or HSV-2 genital infection. The global burden has never been quantified. We developed a novel methodology for burden estimation and present first WHO global and regional estimates of the annual number of neonatal herpes cases during 2010–2015.

Methods

Previous estimates of HSV-1 and HSV-2 prevalence and incidence in women aged 15–49 years were applied to 2010–2015 birth rates to estimate infections during pregnancy. Published risks of neonatal HSV transmission were then applied according to whether maternal infection was incident or prevalent with HSV-1 or HSV-2 to estimate neonatal herpes cases.

Findings

Globally the overall rate of neonatal herpes was estimated to be ~10 cases per 100,000 births, equivalent to a best-estimate of ~14,000 cases annually (HSV-1: ~4,000; HSV-2: ~10,000). We estimated that the most neonatal herpes cases occurred in Africa, due to high maternal HSV-2 infection and high birth rates. HSV-1 contributed more cases than HSV-2 in the Americas, Europe and Western Pacific. High rates of genital HSV-1 infection and moderate HSV-2 prevalence meant the Americas had the highest overall rate. However, our estimates are highly sensitive to the core assumptions, and considerable uncertainty exists for many settings given sparse underlying data.

Interpretation

These neonatal herpes estimates mark the first attempt to quantify the global burden of this rare but serious condition. Better primary data collection on neonatal herpes is critically needed to reduce uncertainty and refine future estimates. This is particularly important in resource-poor settings where we may have underestimated cases. Nevertheless, these first estimates suggest development of new HSV prevention measures such as vaccines could have additional benefits beyond reducing genital ulcer disease and HSV-associated HIV transmission, through prevention of neonatal herpes.

Funding

World Health Organization

Effect of Condom Use on Per-act HSV-2 Transmission Risk in HIV-1, HSV-2-discordant Couples

BACKGROUND

The efficacy of condoms for protection against transmission of herpes simplex virus type 2 (HSV-2) has been examined in a variety of populations with different effect measures. Often the efficacy has been assessed as change in hazard of transmission with consistent vs inconsistent use, independent of the number of acts. Condom efficacy has not previously measured on a per-act basis.

METHODS

We examined the per-act HSV-2 transmission rates with and without condom use among 911 African HSV-2 and human immunodeficiency virus type 1 (HIV-1) serodiscordant couples followed for an average of 18 months in an HIV prevention study. Infectivity models were used to associate the log10 probability of HSV-2 transmission over monthly risk periods with reported numbers of protected and unprotected sex acts. Condom efficacy was computed as the proportionate reduction in transmission risk for protected relative to unprotected sex acts.

RESULTS

Transmission of HSV-2 occurred in 68 couples, including 17 with susceptible women and 51 with susceptible men. The highest rate of transmission was from men to women: 28.5 transmissions per 1000 unprotected sex acts. We found that condoms were differentially protective against HSV-2 transmission by sex; condom use reduced per-act risk of transmission from men to women by 96% (P < .001) and marginally from women to men by 65% (P = .060).

CONCLUSIONS

Condoms are recommended as an effective preventive method for heterosexual transmission of HSV-2.

Plasma and cerebrospinal fluid herpes simplex virus levels at diagnosis and outcome of neonatal infection

OBJECTIVE

To evaluate the utility of quantitative herpes simplex virus (HSV) polymerase chain reaction (PCR) levels for prognosis and management of neonatal HSV disease.

STUDY DESIGN

Clinical and virologic data were abstracted by medical record review from neonatal HSV cases treated at Seattle Children's Hospital between 1993 and 2012. HSV PCR results from plasma (n = 47), cerebrospinal fluid (n = 56), or both (n = 40) at the time of diagnosis were available from 63 infants; 26 with skin-eye-mouth (SEM), 18 with central nervous system (CNS), and 19 with disseminated (DIS) disease.

RESULTS

Plasma HSV PCR was positive in 78% of the infants with SEM, 64% with CNS and 100% with DIS disease. Mean plasma viral level was 2.8 log10 copies/mL in SEM, 2.2 log10 copies/mL in CNS, and 7.2 log10 copies/mL in DIS infants. The HSV levels were higher among infants who died compared with surviving infants, 8.1 log10 copies/mL (range 7.7-8.6) vs 3.8 log10 copies/mL (range 0.0-8.6), P = .001, however, level of HSV DNA in the cerebrospinal fluid or in plasma did not correlate with neurologic outcome. Dynamics of HSV clearance from plasma during high-dose acyclovir treatment showed single-phase exponential decay with a median viral half-life of 1.26 days (range: 0.8-1.51).

CONCLUSIONS

Plasma HSV levels correlate with clinical presentation of neonatal HSV disease and mortality, but not neurologic outcome.

Global estimates of prevalent and incident herpes simplex virus type 2 infections in 2012

Background

Herpes simplex virus type 2 (HSV-2) infection causes significant disease globally. Adolescent and adult infection may present as painful genital ulcers. Neonatal infection has high morbidity and mortality. Additionally, HSV-2 likely contributes substantially to the spread of HIV infection. The global burden of HSV-2 infection was last estimated for 2003. Here we present new global estimates for 2012 of the burden of prevalent (existing) and incident (new) HSV-2 infection among females and males aged 15–49 years, using updated methodology to adjust for test performance and estimate by World Health Organization (WHO) region.

Methods and Findings

We conducted a literature review of HSV-2 prevalence studies world-wide since 2000. We then fitted a model with constant HSV-2 incidence by age to pooled HSV-2 prevalence values by age and sex. Prevalence values were adjusted for test sensitivity and specificity. The model estimated prevalence and incidence by sex for each WHO region to obtain global burden estimates. Uncertainty bounds were computed by refitting the model to reflect the variation in the underlying prevalence data. In 2012, we estimate that there were 417 million people aged 15–49 years (range: 274–678 million) living with HSV-2 infection world-wide (11.3% global prevalence), of whom 267 million were women. We also estimate that in 2012, 19.2 million (range: 13.0–28.6 million) individuals aged 15–49 years were newly-infected (0.5% of all individuals globally). The highest burden was in Africa. However, despite lower prevalence, South-East Asia and Western Pacific regions also contributed large numbers to the global totals because of large population sizes.

Conclusions

The global burden of HSV-2 infection is large, leaving over 400 million people at increased risk of genital ulcer disease, HIV acquisition, and transmission of HSV-2 to partners or neonates. These estimates highlight the critical need for development of vaccines, microbicides, and other new HSV prevention strategies.

Clinical assessment of assays for diagnosis of herpes simplex infection

It is becoming increasingly clear that the herpes simplex viruses (HSVs) 1 and 2 constitute a major, global, public health problem, particularly as genital herpes is implicated in the causation of a significant percentage of onwards transmission of the HIV virus. A major factor in the transmission of HSV is that most carriers are unaware of their diagnosis. In the last few years, the development of nucleic acid amplification technology and type-specific antibody serology to test for HSV-1 and -2 has contributed significantly to the accurate diagnosis of these infections. Despite guidance to the contrary, there is still much use of less sensitive tests such as viral culture and antibody testing based on crude antigen. It is essential that we use the most sensitive and specific diagnostic tests if we are to curb this epidemic.

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.

Case-crossover analysis of condom use and herpes simplex virus type 2 acquisition

BACKGROUND

Although growing evidence suggests that condoms offer moderate protection against herpes simplex virus type 2 (HSV-2), inability to control for unknown or unmeasured confounders associated with sexual activity may reduce the accuracy of the estimates. The case-crossover design offers increased control of individual-level confounders, and was thus used with the aim of producing a more accurate estimate of the effect of condom use on HSV-2 acquisition.

METHODS

Data were pooled from 6 prospective studies that measured HSV-2 status at enrollment and over follow-up, and included periodic self-reported condom use and sexual activity. Sexual activity contemporaneous with acquisition was assigned to a case period; earlier sexual activity was assigned to a control period. Conditional logistic regression was used to assess differences in behavior during the case and control periods.

RESULTS

One hundred ninety-one eligible participants acquired HSV-2 during follow-up. This approach detected a 3.6% increase in the odds of HSV-2 acquisition with each unprotected act (odds ratio = 1.036; 95% confidence interval: 1.021-1.052), but no increase in the odds of acquisition associated with protected acts (odds ratio = 1.008; 95% confidence interval: 0.987-1.030).

CONCLUSIONS

This analysis suggests that condoms offer significant protection against HSV-2 transmission.

Discovery of potential diagnostic and vaccine antigens in herpes simplex virus 1 and 2 by proteome-wide antibody profiling

Routine serodiagnosis of herpes simplex virus (HSV) infections is currently performed using recombinant glycoprotein G (gG) antigens from herpes simplex virus 1 (HSV-1) and HSV-2. This is a single-antigen test and has only one diagnostic application. Relatively little is known about HSV antigenicity at the proteome-wide level, and the full potential of mining the antibody repertoire to identify antigens with other useful diagnostic properties and candidate vaccine antigens is yet to be realized. To this end we produced HSV-1 and -2 proteome microarrays in Escherichia coli and probed them against a panel of sera from patients serotyped using commercial gG-1 and gG-2 (gGs for HSV-1 and -2, respectively) enzyme-linked immunosorbent assays. We identified many reactive antigens in both HSV-1 and -2, some of which were type specific (i.e., recognized by HSV-1- or HSV-2-positive donors only) and others of which were nonspecific or cross-reactive (i.e., recognized by both HSV-1- and HSV-2-positive donors). Both membrane and nonmembrane virion proteins were antigenic, although type-specific antigens were enriched for membrane proteins, despite being expressed in E. coli.

Performance of HSV-2 type specific serological tests in men in Kenya

This study compared five serological tests with Western blot from University of Washington to determine the most accurate method for detecting antibodies to herpes simplex virus type 2 (HSV-2) in a male population in Kisumu, Kenya. A random sample of 250 fishermen from 18 beaches along Lake Victoria underwent serological testing by two generations of the HerpeSelect HSV-2 ELISA ("Focus Gen 1" and "Focus Gen 2"), Kalon HSV-2 ELISA ("Kalon"), Biokit HSV-2 Rapid Test ("Biokit"), and HerpeSelect Express Rapid HSV-2 ("Express") against the Western blot test ("WB") as the "gold standard". Sensitivity and specificity of tests in this population with a high prevalence of HSV-2 (58% by WB) were: Focus Gen 1: 98.6% and 63.5%; Focus Gen 2: 99.3% and 52.3%; Biokit: 66% and 90.9%; Express: 99.3% and 44.3% and Kalon: 98.6% and 85.7%. Increasing the positive cut-off value improved the specificity of the Focus Gen 2-84.9% and Kalon to 92.2%. Focus Gen 2 offered no improvement in specificity over that of Focus Gen 1. Neither rapid assay could be recommended as either a stand-alone assay or as a confirmatory test. The results of Kalon using a cut-off of 1.5 were the most concordant with those of WB for all the approaches tested. However, low positive Kalon test results should be interpreted with caution as they could reflect early seroconversion or false positive results.

Herpes simplex virus infection in pregnancy and in neonate: status of art of epidemiology, diagnosis, therapy and prevention

Herpes simplex virus (HSV) infection is one of the most common viral sexually transmitted diseases worldwide. The first time infection of the mother may lead to severe illness in pregnancy and may be associated with virus transmission from mother to foetus/newborn. Since the incidence of this sexually transmitted infection continues to rise and because the greatest incidence of herpes simplex virus infections occur in women of reproductive age, the risk of maternal transmission of the virus to the foetus or neonate has become a major health concern. On these purposes the Authors of this review looked for the medical literature and pertinent publications to define the status of art regarding the epidemiology, the diagnosis, the therapy and the prevention of HSV in pregnant women and neonate. Special emphasis is placed upon the importance of genital herpes simplex virus infection in pregnancy and on the its prevention to avoid neonatal HSV infections.

Rapid diagnostic methods in sexually transmitted infections

Sexually transmitted infections (STIs) are common infections throughout the developed and the developing world. It is estimated that worldwide there are 1 million new cases per day of curable bacterial STIs. As part of the World Health Organization 2001 Sexually Transmitted Diseases Diagnostics Initiative, the organization explored the need for simple, affordable, point-of-care STI testing for curable bacterial STIs. This article reviews the evidence supporting the implementation of currently available rapid tests for five common STIs: syphilis, gonorrhea, chlamydia, HIV, and herpes.

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.

Prevalence of HSV-2 antibody in a Melbourne antenatal population attending a tertiary obstetric hospital

OBJECTIVE

To determine the herpes simplex virus 2 (HSV-2) seroprevalence rate in a Melbourne antenatal cohort.

DESIGN

Prospective collection of serum and questionnaires in 1371 women attending an outpatient antenatal clinic.

SETTING

A tertiary obstetric hospital in metropolitan Melbourne.

PARTICIPANTS

Women aged 18 years or older attending an antenatal clinic appointment.

MAIN OUTCOME MEASURE

Seroprevalence rate of HSV-2 using an ELISA-based- type-specific serological assay.

RESULTS

The overall HSV-2 seroprevalence rate in women was 13.6%. Only 0.4% of assays were equivocal and required confirmation by Western blot analysis. By multivariate analysis, HSV-2 seroprevalence was found to be associated with increasing age (odds ratio (OR) 4.63; confidence interval (CI) 1.86, 11.52 for age greater than 40 years), increasing number of sexual partners (OR 4.07, CI 2.13, 7.7 for five or more) and a past history of genital herpes in the index case (OR 5.48, CI 2.77, 10.87) or in a current or previous partner (OR 8.29, CI 4.15 to 16.56).

CONCLUSIONS

HSV-2 seroprevalence rates in Melbourne are comparable to other similar populations in Australia. Routine antenatal screening for HSV-2 is probably not warranted but targeted screening based on numbers of sexual partners or a history of genital herpes in partners may be justified.

Rapid, sensitive, and specific lateral-flow immunochromatographic point-of-care device for detection of herpes simplex virus type 2-specific immunoglobulin G antibodies in serum and whole blood

Herpes simplex virus type 2 (HSV-2) is a common human pathogen that can cause a variety of clinical manifestations in humans. In order to provide near-patient results to allow for faster counseling and treatment, a rapid point-of-care test that is accurate and simple to use is desirable. Here, we describe the development and evaluation of an HSV-2 immunoglobulin G (IgG)-specific antibody lateral-flow immunochromatographic assay (LFIA) based on colloidal gold nanoparticles. A total of 359 serum samples and 100 whole-blood samples were tested in the newly developed HSV-2 LFIA. Serum results were compared to those from the HerpeSelect HSV-2 enzyme-linked immunosorbent assay (ELISA), and whole-blood sample results were compared to those of both ELISA and HerpeSelect HSV-1 and -2 immunoblotting (IB). The sensitivity of the HSV-2 LFIA compared to that of the HerpeSelect ELISA was 100% (89/89), and the specificity was 97.3% (257/264). Cross-reactivity with HSV-1 IgG-positive serum samples was observed in 2.6% (5/196) of samples, 2.9% (1/34) for rubella virus, and 6.2% (1/16) for Epstein-Barr virus. No cross-reactivity in varicella-zoster virus or cytomegalovirus IgG-positive serum samples was observed. No interference was observed from bilirubin-, triglyceride-, albumin-, or hemoglobin-spiked samples. The concordance of the LFIA results between capillary whole blood, EDTA-treated venous whole blood, heparin-treated venous whole blood, and serum was 99% (99/100). In conclusion, the LFIA for HSV-2 IgG-specific antibodies demonstrated excellent sensitivity, specificity, and concordance for both serum and whole-blood samples compared to the sensitivity, specificity, and concordance of both HSV-2 ELISA and IB.

Effect of sexually transmitted disease (STD) coinfections on performance of three commercially available immunosorbent assays used for detection of herpes simplex virus type 2-specific antibody in men attending Baltimore, Maryland, STD clinics

Two hundred seventy-nine serum samples from men attending sexually transmitted disease (STD) clinics in Baltimore, Maryland, were tested for herpes simplex virus type 2 (HSV-2)-specific antibody by three immunosorbent glycoprotein G-2-based assays (the Kalon, Focus, and Biokit assays). The results for all samples with positive results were confirmed by Western blotting (91/279; 32.6% HSV-2 seroprevalence). All patients were also tested for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Mycoplasma genitalium, human immunodeficiency virus type 1, and hepatitis C virus. The Kalon assay performed very well with samples from this population (90.8% sensitive, 99.4% specific), whereas the Focus assay had a sensitivity (82.6%) much lower than that shown previously. For 19.7% of the samples, the Biokit assay gave an indeterminate result. It was found that the odds of a sample having a Biokit assay indeterminate result compared to that of having a definitive positive or negative results were 3.88 times greater for subjects concurrently infected with N. gonorrhoeae, after the effects of other STDs were controlled for (P = 0.001; 95% confidence interval, 1.78, 8.45). Unfortunately, we were unable to control for HSV-1 infection status in the regression model, which, on the basis of chi(2) analysis, might also affect the clarity of the Biokit test. The recommended index cutoff value of 1.1 for the Focus and Kalon assays was found to be optimal for this population.

Prevalence of herpes simplex virus types 1 and 2 among children and adolescents attending a sexual abuse clinic

BACKGROUND

Children and adolescents with a history of sexual abuse are at risk for acquiring herpes simplex virus (HSV) type 2. We evaluated the prevalence of HSV-1 and HSV-2 and the usefulness for this population of 2 commercially available tests.

METHODS

Sera from 150 children seen in a sexual abuse clinic were analyzed for type-specific HSV antibodies using Focus HerpeSelect HSV-2 ELISA (Focus), Biokit HSV-2 Rapid Test (Biokit), and by Western blot (WB).

RESULTS

The patient sample was 81% female, had a mean age of 11.6 years (range, 1 to 18 years), and was 46% Caucasian, 28% Hispanic, 25% African American, and 2% other. According to WB, 77 (51%) of the children were HSV-1 seropositive. For HSV-2, there was 1 "true positive" (positive by all 3 tests) and 1 patient whose serum had atypical HSV-2 bands by WB but was positive by Focus. There were 6 sera that were positive by Focus and negative by WB. Index values of these 6 Focus tests were not predictive of WB status. For the 105 samples for which Biokit data were available, all samples were concordant with WB.

CONCLUSIONS

The findings of this study suggest that routine screening for HSV-2 in sexually abused children does not have a high yield. The Focus test has an unacceptably high rate of false-positive results in children; however, Biokit may be an acceptable substitute for WB in evaluating children for HSV-2 antibodies.

Use of "biokit HSV-2 Rapid Assay" to improve the positive predictive value of Focus HerpeSelect HSV-2 ELISA

BACKGROUND

Commercially available assays to detect antibodies to the herpes simplex virus type 2 (HSV-2)-specific glycoprotein gG-2 have markedly improved serologic diagnosis of HSV-2 infection. However, even tests with high specificity can have low positive predictive values in low prevalence populations. HSV-2 is a chronic, life-long viral infection that requires both medical attention and potential alterations in health care strategy. As such, the concern for false positive diagnoses is high confirmatory testing is routine for other viral serologies such as HIV and hepatitis C. We evaluated such a strategy for HSV-2 serology by using an easily performed commercial test, biokitHSV-2 rapid test ("Biokit"; Biokit USA, Lexington MA) as a confirmatory test for the widely used gG-2 specific serology ("Focus;" HerpeSelect HSV-2 ELISA; Focus Diagnostics, Cypress CA).

METHODS

We tested 782 sera by Focus HSV-2 ELISA, Biokit, and the current gold standard test, Western blot (WB).

RESULTS

The positive predictive value of the Focus HSV-2 ELISA increased from 80.5% to 95.6% when Biokit testing was performed on sera that were initially positive by Focus HSV-2 ELISA. Confirmatory testing increased the specificity markedly among sera with Focus EIA values between 1.1 and 3.5: only 35% of low positive (index values 1.1-3.5) Focus HSV-2 ELISA results confirmed as positive by Biokit and WB compared with 92% of those with index values >3.5. Mathematical modeling of the data resulted in expected positive predictive values over 98% for populations with antibody prevalences typical of clinical practices in the US and Europe.

CONCLUSION

Confirmatory Biokit testing of positive Focus HSV-2 ELISA results is fast, easy, and effective in reducing falsely positive HSV-2 antibody results. Patients, clinicians, and laboratories could benefit from the enhanced specificity of this simple HSV-2 serologic test combination.

Genital Herpes Complicating Pregnancy

Approximately 22% of pregnant women are infected with herpes simplex virus (HSV)-2, and 2% of women will acquire HSV during pregnancy. Remarkably, up to 90% of these women are undiagnosed because they are asymptomatic or have subtle symptoms attributed to other vulvovaginal disorders. Diagnosis of genital herpes relies on laboratory confirmation with culture or polymerase chain reaction assay of genital lesions and type-specific glycoprotein G-based serologic testing. Neonatal herpes is the most severe complication of genital HSV infection and is caused by contact with infected genital secretions at the time of labor. Maternal acquisition of HSV in the third trimester of pregnancy carries the highest risk of neonatal transmission. Despite advances in the diagnosis and treatment of neonatal herpes, little change in the incidence or serious sequelae from this infection has occurred. As such, prevention of the initial neonatal infection is critically important. Obstetricians are in a unique position to prevent vertical HSV transmission by identifying women with genital lesions at the time of labor for cesarean delivery, prescribing antiviral suppressive therapy as appropriate, and avoiding unnecessary invasive intrapartum procedures in women with genital herpes. Enhanced prevention strategies include identification of women at risk for HSV acquisition during pregnancy by testing women and possibly their partners for HSV antibodies and providing counseling to prevent transmission to women in late pregnancy.

Predictors of Herpes Simplex Virus Type 2 Antibody Positivity Among Persons With No History of Genital Herpes

BACKGROUND

The demographic, historical, and behavioral factors that predict a positive herpes simplex virus type 2 (HSV-2) antibody test in persons without a history of genital herpes have not been well-defined.

METHODS

Individuals (age 14-30 years) without a history of genital herpes completed a questionnaire and were offered free HSV-2 antibody testing. Factors from the questionnaire were correlated with the HSV-2 antibody result.

RESULTS

Univariate analysis showed that female gender was significantly associated with positive test results. In gender-specific, multiple logistic regression models, a positive HSV-2 antibody test among men was associated with older age, non-white race, and a history of sexually transmitted disease (STD). Gender-specific symptom scores from the questionnaire were not predictive in either gender, but the gender-common symptom score was marginally predictive of a positive HSV-2 antibody test in women. Among women, older age, non-white race, and STD history predicted a positive test.

CONCLUSIONS

Among young persons with no history of genital herpes who agreed to HSV-2 antibody testing, increasing age, non-white race, and a history of an STD were predictors of a positive test. A history of frequent pain, itching, burning, and rashes in the anogenital region was marginally associated with positive HSV-2 tests in women. These results might help guide selective use of HSV-2 antibody screening.

Performance and use of a ribonucleotide reductase herpes simplex virus type-specific serological assay

In response to the increasingly evident need for herpes simplex virus (HSV) serotype-specific serologic assays that rely on proteins other than glycoprotein-G (gG), we developed a rapid serologic assay that is based on type-specific epitopes within the large subunit of HSV ribonucleotide reductase (R1). The assay (Au-2 enzyme-linked immunosorbent assay [ELISA]) uses an HSV type 2 (HSV-2) R1 peptide antigen. It provides a reliable method for detecting serotype-specific antibody to a protein other than gG-2. The Au-2 ELISA has high sensitivity and specificity as determined by direct comparison to Western blotting, a widely accepted "gold standard," and to ELISA with an HSV-1 R1 peptide (Au-1). The use of the Au-2 ELISA in conjunction with the gG-2-based assays will improve the sensitivity and specificity of serologic diagnosis and patient management.

Performance of the focus and Kalon enzyme-linked immunosorbent assays for antibodies to herpes simplex virus type 2 glycoprotein G in culture-documented cases of genital herpes

Glycoprotein G-based herpes simplex virus type 2 (HSV-2) enzyme-linked immunosorbent assays from Focus and Kalon were performed with specimens from 118 patients with culture-documented genital herpes episodes, and their results were compared. Sensitivity was 52% by Kalon and 86% by Focus for first HSV-2 episodes and 100% (for each of the two tests) for recurrent HSV-2. Median times to seroconversion were 120 days by the Kalon assay, 21 days by the Focus assay, and 68 days by Western blotting assay. Values for specificity were 100% (Kalon) and 93% (Focus).

Time course of seroconversion by HerpeSelect ELISA after acquisition of genital herpes simplex virus type 1 (HSV-1) or HSV-2

BACKGROUND

HerpeSelect HSV-1 and HSV-2 ELISAs are glycoprotein G-based, type-specific antibody detection tests that are approved by the US Food and Drug Administration for diagnosis of genital herpes.

GOAL

The goal was to determine seroconversion times by means of HerpeSelect ELISAs.

STUDY DESIGN

Four-hundred thirteen sera from 113 patients with recently acquired genital herpes were tested by HerpeSelect ELISAs and Western blot (WB). Thirty-one patients had primary genital HSV-1 (group 1), 56 had primary HSV-2 (group 2), and 26 had prior HSV-1 antibodies and newly acquired HSV-2 (group 3).

RESULTS

Median interval from onset of symptoms to seroconversion was 25 days, as determined by HerpeSelect HSV-1, versus 33 days by WB for group 1; 21 days by HerpeSelect HSV-2 versus 40 days by WB (group 2; P = 0.0005); and 23 days by HerpeSelect HSV-2 ELISA versus 47 days by WB (group 3; P = 0.02). In long-term follow-up, transient reversion to HerpeSelect negativity occurred in 3 of 31 HSV-1-infected subjects (10%) and in 2 of 82 HSV-2-infected subjects (2%).

CONCLUSION

Seroconversion to HSV-2 was determined faster by HerpeSelect than by WB.

Testing for HSV-2 infection among pregnant teens: implications for clinical practice

OBJECTIVES

To pilot test the feasibility of screening pregnant teens for HSV-2 infection during their first prenatal visit.

STUDY DESIGN

A cross-sectional study of 127 African-American adolescent females recruited during their first attendance to a prenatal clinic in a large urban hospital. A rapid serologic test (POCkit, manufactured by Diagnology Inc.) was used to assess HSV-2. The test uses a membrane-based immunoassay to detect circulating IgG antibodies to a specific antigen obtained from HSV-2 (semi-purified glycoprotein G2).

RESULTS

More than one-fifth (21.3%) of the adolescents tested positive for HSV-2; only 1 adolescent was previously aware of her infection. Older adolescents and those reporting a history of other STDs were significantly more likely to test positive for HSV-2.

CONCLUSIONS

Testing for HSV-2 in early pregnancy may be an efficient strategy for (1) initiating patient education designed to promote adoption of protective behaviors among adolescents at risk of HSV-2 acquisition during the remainder of their pregnancy and (2) teaching those who test positive how to recognize symptoms of HSV-2 outbreaks; patients reporting recurrent outbreaks during pregnancy may benefit from predelivery assessment.

Serological testing for herpes simplex virus (HSV)-1 and HSV-2 infection

Serological tests for herpes simplex virus (HSV) that can accurately distinguish between HSV-1 and HSV-2 are now commercially available. These tests detect antibodies to HSV glycoproteins G-1 and G-2, which evoke a type-specific antibody response. Focus Technologies produces the HerpeSelect-1 and HerpeSelect-2 enzyme-linked immunosorbent assay tests and the HSV-1 and HSV-2 HerpeSelect1/2 Immunoblot. Diagnology has marketed POCkit-HSV-2, a point-of-care test for HSV-2 that allows blood from a finger stick to be tested in a clinic. These tests can be used to confirm a genital herpes diagnosis, establish diagnosis of HSV infection in patients with atypical complaints, identify asymptomatic carriers, and identify persons at risk for acquiring HSV. Potential settings for use of these tests include sexually transmitted disease clinics, prenatal clinics, and clinics that care for patients with human immunodeficiency virus. Patient interest in HSV serological tests appears high.

Projection of the future dimensions and costs of the genital herpes simplex type 2 epidemic in the United States

BACKGROUND

Infection with herpes simplex virus type 2 (HSV-2) currently affects approximately 22% of adult Americans and increased markedly in prevalence between the late 1970s and early 1990s. Although some estimates of the costs of prevalent disease due to HSV-2 are available, selection of interventions to prevent HSV-2 infection, as well as evaluation of their potential cost-effectiveness, should take into account projected future costs that will result if the epidemic is left unchecked.

GOAL

The goal was to estimate the future health and economic consequences attributable to the HSV-2 epidemic in the absence of interventions to slow the epidemic.

STUDY DESIGN

A mathematical model was constructed to project future increases in HSV-2 seroprevalence in the United States. The probability of heterosexual transmission of HSV-2 was estimated from cross-sectional estimates of infection prevalence reported by the National Health and Nutrition Examination Survey (NHANES). Per-infection expected costs were calculated on the basis of data obtained from the published medical literature. RESULTS Without intervention, the prevalence of HSV-2 infection among individuals aged 15 to 39 years was projected to increase to 39% among men and 49% among women by 2025. Annual incidence was projected to increase steadily between 2000 and 2025, from 9 to 26 infections per 1,000 men and from 12 to 32 infections per 1,000 women in this age group. The cost of incident infections in the year 2000 were estimated to be $1.8 billion; the cost of incident infections was predicted to rise to $2.5 billion by 2015 and $2.7 billion by 2025. The projected cumulative cost of incident HSV-2 infections occurring over the next 25 years was estimated to be $61 billion; at a 3% discount rate, this sum has a present value of $43 billion.

CONCLUSION

The costs of incident HSV-2 infection in the United States are substantial and can be expected to increase as both the incidence and prevalence of this disease increase in the first half of the century. The level of resource allocation for HSV-2 prevention strategies should reflect the economic benefits that would result from control of this epidemic.

Use of a fragment of glycoprotein G-2 produced in the baculovirus expression system for detecting herpes simplex virus type 2-specific antibodies

Fragments of glycoprotein G (gG-2(281-594His)), comprising residues 281 to 594 of herpes simplex virus type 2 (HSV-2), glycoprotein G of HSV-1 (gG-1(t26-189His)), and glycoprotein D of HSV-1 (gD-1(1-313)), were expressed in the baculovirus expression system to develop an assay for the detection of HSV-1 and HSV-2 type-specific antibodies. The expression of the gG-1(t26-189His) and gG-2(281-594His) fragments was analyzed by Western blotting using monoclonal antibodies LP10 and AP1, respectively. The molecular masses of the major products of gG-1(t26-189His) and the fragment of gG-2(281-594His) were 36 to 39 kDa and 64 to 72 kDa, respectively. Human sera positive for HSV-1 reacted with gG-1(t26-189His), sera positive for HSV-2 reacted with the gG-2(281-594His) fragment, and sera positive for both types reacted with gG-1(t26-189His) and gG-2(281-594His) in Western blotting. The human sera recognized polypeptides of gG-2(281-594His) with molecular masses of 57 to 67 and 120 to 150 kDa and additional faint bands of 21, 29, and 45 kDa. The recombinant gG-1(t26-189His) and the recombinant gG-2(281-594His) fragment were used as type-specific antigens for the detection of HSV-1- and HSV-2-specific antibody responses in human sera, respectively. As type-common antigens, an extract of HSV-1-infected Vero cells and recombinant gD-1(1-313) were used. An enzyme-linked immunosorbent assay to detect type-specific antibodies was developed, and the sensitivity and specificity were evaluated by comparison with commercial tests by using sera obtained from different sources. The sensitivity and specificity were 91.5 and 95.5%, respectively, compared to the Gull assay. The gG-2(281-594His) fragment can be obtained in relatively large quantities at low cost.

Infectious diseases. 6: Sexually transmitted infections: new diagnostic approaches and treatments

1. Commercially available nucleic acid amplification assays (eg, polymerase or ligase chain reaction) are now the "gold standard" tests for genital chlamydial infection and also have a role in screening for gonococcal infection. 2. Single-dose oral antibiotics are available for treatment of Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis infections. 3. Strains of N. gonorrhoeae in urban Australia are often penicillin resistant, while strains from South East Asia and those in homosexually active men may show high-level resistance to quinolones. 4. Imiquimod, a novel immune-response modifier, is now available for effective, safe, self-administered treatment of genital warts. 5. The Pap smear remains the cornerstone of screening for precursor lesions of cervical cancer, but human papillomavirus genotyping may have a role in clinical decision-making for women with equivocal or early precancerous lesions. 6. Treatment of primary genital herpes changes the clinical course, and long-term suppressive therapy is effective for those with multiple recurrences. New technologies have made diagnosis and screening easier for patients and clinicians

Evaluation of confirmatory strategies for detection of type-specific antibodies against herpes simplex virus type 2

In this study, the optimal combination of three commercial glycoprotein G-2 (gG-2)-based herpes simplex virus type 2 (HSV-2) type-specific enzyme-linked immunosorbent assays (Euroimmun anti-HSV-2 immunoglobulin G [IgG] ELISA [Eu2], Gull HSV-2-specific IgG ELISA [Gu2], and Radim HSV-2 IgG ELISA [Ra2]) and one gG-2-based HSV-2-specific immunoblot (Euroimmun anti-HSV-1/HSV-2 gG Western blot [EuW]) was determined with regard to diagnostic performance and cost efficiency. Two hundred fifty serum samples were included in this study, 194 of which were from female prostitutes. When a formal primary "gold standard" was defined based on majority agreement of the commercial tests, with EuW being decisive in stand-off situations, the sensitivity and specificity of the assays in the samples from prostitutes were as follows: Eu2, 100 and 89.22%; Gu2, 94.44 and 96.08%; Ra2, 61.18 and 95.10%; and EuW, 98.90 and 100%. The most cost-effective confirmatory strategy in the samples from prostitutes was screening with Eu2, retesting positive and equivocal samples with Gu2, and resolving the remaining discordant results with EuW (estimated additional costs per sample, 79.02%; sensitivity, 100%; positive predictive value, 96.81%). Applying a self-developed gG-2-independent assay to the discordant and concordant negative samples in the samples from prostitutes suggested that the primary gold standard may have missed six HSV-2-positive samples. In conclusion, confirmatory strategies based on commercial gG-2-dependent seroassays result in an increase in the specificity of HSV-2-specific serology. However, further improvement of the sensitivity of current HSV-2-specific serology may require the additional exploitation of the gG-2-independent type-specific antibody response.

Seroprevalence of herpes simplex virus types 1 and 2 in HIV-infected and uninfected homosexual men in a primary care setting

BACKGROUND

Genital herpes is usually caused by herpes simplex virus type 2 (HSV-2), with infections often being unrecognised by patients and/or clinicians. HSV-2 infections may be a risk factor for the transmission of human immunodeficiency virus (HIV) infection. Reliable tests for type-specific HSV antibodies are now readily available.

OBJECTIVES

To determine the seroprevalence of HSV-1 and -2 in HIV-seronegative gay men in a primary care setting in Melbourne, Australia, and to compare it with the rate in HIV-infected gay men. To assess the utility in a clinical setting of a type-specific HSV enzyme linked immunosorbent assay (ELISA) as compared with western blot.

STUDY DESIGN

We recruited a total of 300 HIV-seronegative homosexual men attending for HIV antibody testing, and HIV-infected men attending for CD4 lymphocyte count and viral load estimation. The subjects completed a questionnaire, and sera were sent for total IgG HSV testing and testing by Gull type-specific HSV ELISA assay. Selected serum samples were retested by western blotting and the results analysed.

RESULTS

In total, 168 HIV-antibody negative men and 132 HIV-antibody positive men were recruited. Of all subjects, 73.3% had HSV-1 antibodies. This proportion did not differ between HIV-seronegative and seropositive men (P=0.48). About twenty percent of HIV-seronegative men and 61% of HIV-seropositive men had antibodies to HSV-2 (P<0.0001); 75.6% of HIV-seronegative men with antibodies to HSV-2 gave no history of genital herpes, as did 66.7% of HIV-seropositive men. Overall, in using the type-specific ELISA (Gull) assay, false negative, false positive or equivocal results were obtained in 33/300 (11%) of samples tested compared with western blot.

CONCLUSIONS

High rates of HSV-2 infection were found in homosexual males, with the rate for HIV-seropositive men being over twice that for HIV uninfected men. Most subjects were not aware of their infection with HSV-2. HIV-infected individuals were also older and had higher numbers of sexual partners, but we were unable to unambiguously establish that these variables contributed to the difference in HSV-2 seroprevalence rates. The Gull type-specific assay for HSV antibodies has significant problems with sensitivity and specificity at a discrepancy rate of 11%. Caution is advised in using this type-specific commercial assay for clinical purposes.

Sorting out the new HSV type specific antibody tests

This review will delineate performance characteristics and limitations, as far as they are known, of the new glycoprotein G based, type specific HSV serologies. Several of these tests have been FDA approved in the United States for use in adults. With the departure of Gull/Meridian from the HSV serology market, it is important for clinicians to understand the sources and claims of the remaining type specific tests. Moreover, inaccurate tests using crude antigen preparations remain on the market. These tests are identified based on product insert information provided by company representatives.

Premarket evaluation of the POCkit HSV-2 type-specific serologic test in culture-documented cases of genital herpes simplex virus type 2 [see comment]

BACKGROUND AND OBJECTIVES

The genital herpes epidemic continues, in part, because patients with subclinical or atypical presentations cannot be identified by most herpes simplex virus (HSV) antibody tests. A new product, POCkit HSV-2, has been developed to rapidly and accurately detect antibodies to HSV type 2 (HSV-2) in capillary blood or serum.

GOAL

Sera from patients with culture-documented genital or oral herpes were tested to determine the sensitivity and specificity of the POCkit HSV-2 rapid point-of-care antibody test (Diagnology, Belfast, Northern Ireland).

STUDY DESIGN

Sera from 50 patients with culture-documented HSV type 1 (9 oral, 41 genital) and from 253 patients with genital HSV-2 were tested by POCkit HSV-2 for HSV-2 antibodies. Each subject had a positive culture for HSV within 6 months of serum collection. Sera were preselected to include only those that were seropositive to the respective virus subtype by University of Washington Western blot.

RESULTS

Compared with viral culture and Western blot analysis, sensitivity of the POCkit HSV-2 test for HSV-2 antibody was 96%; specificity was 98%.

CONCLUSION

This test provides rapid, accurate identification of HSV-2 antibody in subjects with established HSV infections.

A prospective study of new infections with herpes simplex virus type 1 and type 2. Chiron HSV Vaccine Study Group

BACKGROUND AND METHODS

Herpes simplex virus (HSV) infections are endemic, but the clinical characteristics of newly acquired HSV type 1 (HSV-1) and HSV type 2 (HSV-2) infections in adults have not been rigorously defined. We monitored 2393 sexually active HSV-2-seronegative persons for clinical and serologic evidence of new HSV infection. Of the participants, 1508 were seropositive for HSV-1 and 885 were seronegative. Charts were reviewed in a blinded manner for classification of those with genitourinary or oropharyngeal symptoms. Charts were also reviewed for all 174 persons with HSV seroconversion.

RESULTS

The rates of new HSV-1 and HSV-2 infections were 1.6 and 5.1 cases per 100 person-years, respectively. Of the 155 new HSV-2 infections, 57 (37 percent) were symptomatic, 47 of which (82 percent) were correctly diagnosed at presentation. Among the 74 patients given a clinical diagnosis of genital HSV-2 during the study, 60 were given a correct diagnosis and 14 were given an incorrect diagnosis of genital herpes, for a ratio of true positive results to false positive results of 4:1. Among the 98 persons with asymptomatic HSV-2 seroconversion, 15 percent had genital lesions at some time during follow-up. Women were more likely than men to acquire HSV-2 (P<0.01) and to have symptomatic infection. Previous HSV-1 infection did not reduce the rate of HSV-2 infection, but it did increase the likelihood of asymptomatic seroconversion, as compared with symptomatic seroconversion, by a factor of 2.6 (P<0.001). Of the 19 new HSV-1 infections, 12 were symptomatic. The rates of symptomatic genital HSV-1 infection and oropharyngeal HSV-1 infection were the same (0.5 case per 100 person-years).

CONCLUSIONS

Nearly 40 percent of newly acquired HSV-2 infections and nearly two thirds of new HSV-1 infections are symptomatic. Among sexually active adults, new genital HSV-1 infections are as common as new oropharyngeal HSV-1 infections.