Performance of HerpeSelect and Kalon Assays to Detect Antibodies to Herpes Simplex Virus Type 2 ACCEPTED

Transcription

1 JCM Accepts, published online ahead of print on April J. Clin. Microbiol. doi:./jcm.- Copyright, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved Performance of HerpeSelect and Kalon Assays to Detect Antibodies to Herpes Simplex Virus Type Jérôme LeGoff 1,, Philippe Mayaud, Gérard Gresenguet, Helen A. Weiss, Khonde Nzambi, Eric Frost, Jacques Pepin, Laurent Belec 1 & the ANRS 1-1 Study Group* 1 Université Paris Descartes, Equipe «Immunité et Biothérapie Muqueuse», Unité INSERM Internationale U («Immunologie Humaine»), Centres de Recherches Biomédicales des Cordeliers, & Laboratoire de Virologie, Hôpital Européen Georges Pompidou, Paris, France Laboratoire de Microbiologie, Hôpital Saint-Louis, Paris, France Clinical Research Unit, Department of Infectious and Tropical Diseases; and Infectious Diseases Epidemiology Unit, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK Centre National de Référence des Maladies Sexuellement Transmissibles et du SIDA de Bangui, & Unité de Recherches et d Intervention sur les Maladies Sexuellement Transmissibles et du SIDA, Faculté des Sciences de la Santé, Bangui, Central African Republic West African Project To Combat AIDS and STDs, Accra, Ghana Centre for International Health, University of Sherbrooke, Sherbrooke, Canada *Composition of the ANRS 1-1 Study Group is detailed at the end of the manuscript Running title: HSV- serology in primary and recurrent genital herpes Corresponding author: Jérôme LeGoff, PharmD, PhD, Laboratoire de Microbiologie, Hôpital Saint-Louis, 1 Avenue Claude Vellefaux, Paris, France. Tel: 1 ; Fax: 1 ; electronic address: jerome.le-goff@sls.aphp.fr Word count: ; abstract: ; title: words (1 characters); running title: words ( characters); tables and 1 figure; references: 1. Conflict of interest: none declared - 1 -

2 Abstract Background and aim: Performance of commercial ELISAs to detect herpes simplex virus type (HSV-) antibodies have been inconsistent in African and HIV-positive populations. We compared the performance of HerpeSelect and Kalon gg ELISAs in patients with genital ulcer disease (GUD) in Ghana and the Central African Republic. Methods: Sera from women were tested with HerpeSelect, and a sub-sample (n=1) by Kalon. Ulcer swabs and cervico-vaginal lavages were tested for HSV- DNA by PCR. HSV- seronegative women with detectable genital HSV- DNA were retested 1 and days later for HSV- antibodies by the two ELISAs. Results: (%) women were HerpeSelect -positive at baseline, and (%) had detectable genital (lesional or cervico-vaginal) HSV- DNA. (1%) HerpeSelect -positive samples had low-positive index values (1.1-.), of which % had detectable genital HSV- DNA. Global agreement between the two serological assays was %. Concordance was high (%) for sera negative by HerpeSelect or with high index values (>.). Defining infection detected by HSV- DNA PCR and/or Kalon assay as true infection, 1% of sera with low-positive index values were associated with true HSV- infection. Twenty-five women were identified as having non-primary first episode genital HSV-. Rates of HSV- seroconversion at day 1 were % (/1) with HerpeSelect and % (/1) with Kalon, with additional seroconversions detected by Kalon at day. HIV serostatus did not influence assay performance. Conclusions: Low index values of HerpeSelect may correspond to true HSV- infection, in particular non-primary first episodes of genital HSV- and need to be interpreted in the context of clinical history. Key words: herpes simplex virus type- (HSV-); serology; genital herpes; genital ulcer disease (GUD); Africa - -

3 INTRODUCTION Identification of individuals infected with Herpes simplex virus type (HSV-) is critical for the management of genital herpes, as well as for epidemiological studies and clinical trials. The performance of commercially available assays to detect HSV--specific glycoprotein G (gg) antibodies varies significantly between study populations (). For example, the FDA- approved and widely available HerpeSelect enzyme-linked immunosorbent assay (ELISA) (Focus Technologies) had high sensitivity and specificity, ranging from to %, against the reference HSV- Western blot (WB) assay when testing sera from North American or Western European populations, but significantly lower specificity when testing sera from adult African populations (,, 1). Moreover, concordance between WB and HerpeSelect was found to vary between countries in sub-saharan Africa (,,, ) and according to HIV serostatus (1). HerpeSelect and other assays have been compared in an evaluation study using African sera from population-based surveys, and the Kalon gg-specific ELISA (Kalon Biologicals) was found to be as sensitive and more specific than HerpeSelect against WB (1). Similar results were documented in Brazilian populations using clinico- virological reference groups (1). To increase the specificity of HerpeSelect, some authors have suggested using a higher index value of. for the seropositivity cut-off instead of the manufacturer s recommended cut-off of 1.1 (,, 1, 1). 1 A critical element in evaluating the performance of these assays is the stage of HSV- infection. One study reported that the sensitivity of HerpeSelect increased in patients suffering from genital ulcer disease (GUD) compared to blood donors (), perhaps because HerpeSelect may detect primary genital herpes earlier than Kalon or even WB (1, 1). In the present report, we assessed the performance characteristics of HerpeSelect and Kalon in African patients presenting with symptomatic and molecular-documented genital HSV- infection. - -

4 METHODS Women presenting with GUD at study sites in Ghana and the Central African Republic were enrolled in a randomized placebo-controlled trial of aciclovir mg three times daily for days given in addition to routine syndromic antibacterial GUD treatment () (ClinicalTrials register no. NCT1). Briefly, eligible and consenting women with clinically-verified GUD (including blisters and sores) were interviewed and examined genitally, and samples were obtained and tested as follows: two swabs from the ulcer base were used to determine GUD etiology and to detect lesional HIV-1 RNA, using molecular methods (,,, 1); a cervicovaginal lavage (CVL) was collected to detect and quantify HSV- DNA and HIV-1 RNA in genital secretions, using real-time PCR (); and blood samples were obtained for detection of HSV- antibodies (HerpeSelect, Focus Technologies, Cypress Hill, CA), HIV-1 antibodies and CD lymphocyte counts, as previously described (). Serum samples obtained at days 1 and from women who were HSV- seronegative at day but positive for lesional and/or cervico-vaginal HSV- DNA (i.e. with genital HSV-), were tested using HerpeSelect to detect possible HSV- seroconversion, and their enrolment (day ) samples were tested for HSV-1 antibodies by HerpeSelect gg1 assay (Focus Technologies) to determine if these were cases of primary genital herpes (dually HSV-1 and HSV- seronegative samples) or non-primary first episode HSV- infection (HSV-1 seropositive and HSV- seronegative samples). All samples from a given woman were tested in the same ELISA run. The Kalon gg-specific assay (Kalon Biologicals, Aldershot, UK) was used to test all available sera with HerpeSelect index values ranging from >1.1 to. (n=, out of ), a random selection of sera with index values >., and of sera with index value <. including all cases (n=) of potential HSV- seroconverters (as defined above). - -

5 We calculated the percentage agreement between the two tests and concordance by Cohen s kappa coefficient (k), and we tested for differences in testing positive using McNemar s χ test for paired samples. Chi-square tests were used to compare proportions for unpaired tests, the Wilcoxon ranksum test was used for comparison of medians, and the Spearman's rank test for correlation of categorical variables. - -

6 RESULTS Of 1 women with GUD enrolled into the trial, had HSV- serological results ( and 1 from Ghana and the Central African Republic, respectively). HSV- Seroprevalence was higher in the Central African Republic than in Ghana (% vs 1%; P<.1). Among the 1 with genital samples, HSV- DNA was detected in (%) by PCR in the lesional (n=) or the CVL only (n=1) specimens (with 1 positive for both samples). Table 1 shows the distribution of HerpeSelect index values by genital HSV- DNA status combining results from the two countries since no difference in the distribution of HerpeSelect index values were observed (not shown). Serum samples from (%) women were found HSV--seropositive by HerpeSelect (index value >1.1), of which (1%) had low-positive index values (<.). Samples from a further women were found equivocal (.-1.1), of which one was associated with positive detection of HSV- DNA (in lesional sample). Overall, % (/) of women with low-positive HerpeSelect index values and % (1/) of women with high-positive HerpeSelect index values had molecular evidence of genital HSV- infection (P=.). Of the HSV- seropositive women with genital HSV- DNA, (1%) had index values <.. Among HSV- seropositive women, there was little difference in median index values between women with (median=., interquartile range (IQR):. to.) or without detectable genital HSV- DNA (median=., IQR:. to.1) (P=.). The frequency of recent clinical episode was significantly correlated with HerpeSelect titers. An episode of GUD in the past 1 months was given by 1%, 1%, % and %, respectively, in the groups of patients with negative, equivocal, low-positive, and high-positive HerpeSelect serology (Spearman s rank correlation, P<.1) (Table 1). Table shows results obtained by serological testing using both HerpeSelect and Kalon assays, including suspected first episodes of genital HSV-. Overall agreement between the - -

7 two serological assays was % (/1) or % (1/1), depending on classification of equivocal results with Kalon as negative or positive respectively, and concordance defined by the kappa coefficient was good (κ=.). All samples found negative with HerpeSelect were negative with Kalon. Similarly, all but one of the samples with HerpeSelect index values >. were positive with Kalon. The one discordant sample had high HerpeSelect index value (.) and HSV- DNA detection in both lesional and cervico- vaginal samples. The combined results of negative samples (index values <. with both assays) and high-positive samples (index values >. for HerpeSelect ) gave an agreement of % (1/1), corresponding to a high kappa coefficient (κ=.). In the samples with HerpeSelect index values ranging from >1.1 to., Kalon results were found negative for (%) (of which were associated with detection of genital HSV- DNA), equivocal for (%) (1 positive for HSV- DNA in CVL only), and positive for (%). Assuming detection of genital HSV- DNA (n=) and/or concordant seropositivity with Kalon (n=) as confirmation of HSV- infection, 1% (/) of samples with HerpeSelect index values between >1.1 and. should be considered true HSV- infections, and would have been misclassified using the higher cutoff of. suggested by Hogrefe et al (), and Nascimento et al (1). Among discordant samples between HerpeSelect and Kalon tested for HSV- DNA, % (/) were associated with a positive detection of HSV- DNA (Table ). Finally, among women found seropositive with HerpeSelect and with concomitant genital HSV- DNA, only % (/) were considered as HSV- seropositive with Kalon. Among the women classified as HSV- seronegative or equivocal by HerpeSelect at day who had genital samples, (% of all women in the trial) had genital HSV- DNA detected by PCR (Table 1). These patients presented to the clinics after a median of days - -

8 (range -1 days) following symptom onset. All these women were HSV-1 seropositive by HerpeSelect gg1 assay, thus they were classified as cases of non-primary first episode of genital HSV-. All day sera were also found negative by Kalon. Among these women, 1 were tested at either day 1 or day ( at both days, only at day 1 and only at day ): cases of HSV- seroconversion were detected, by HerpeSelect and by Kalon. HSV- seroconversion occurred earlier with HerpeSelect (Fig.1). At day 1, % (/1) of sera were positive with HerpeSelect compared with only % (/1) with Kalon (P=.1). Four additional seroconversions were observed with Kalon at day, and none by HerpeSelect. The median of HerpeSelect index values for these seroconversion cases was. (range,.1 to 1.) at day 1, and. (range, 1. to 1.) at day. Among cases of non-primary first episode of genital HSV-, four were HIV-seropositive at baseline and one woman seroconverted for HIV within days. All three HIV-seropositive samples which were tested at day showed HSV- seroconversion. Fourty-seven percent (/) of women included in this study were HIV-1 seropositive. The analysis of HSV- serological results according to HIV-1 serostatus did not show any effect of HIV-1 infection on the performance of HerpeSelect. HSV- assay-discordant samples were less frequently HIV-1 seropositive than concordant ones (1% vs %, McNemar s P=1). The median HerpeSelect index values were similar in HIV-1 seropositive and seronegative samples (. vs., P=.)

9 DISCUSSION To our knowledge, this is the first report of an evaluation of HSV- sero-assays among cases of genital herpes documented through molecular methods including cases of non-primary first episodes of genital HSV- in Africa. Previous studies have suggested that the specificity of the HerpeSelect assay to detect HSV- serum antibodies may be lower when using African sera or in HIV-1 seropositive patients (,, 1). A higher positivity cut-off index value of. (instead of the manufacturer s recommended 1.1) has therefore been suggested to increase assay specificity. However, the clinical stage of HSV- infection had not been ascertained in these studies, which may have interfered with the correct interpretation of results. In the present study, we aimed to re-evaluate the significance of low HerpeSelect index values among African patients presenting with GUD. We compared the results obtained with HerpeSelect with those of the Kalon serological assay known to have a high specificity (1, 1). Our results show a % concordance between HerpeSelect and Kalon assays for negative or high-positive (>.) HerpeSelect results, which confirms previous reports of excellent agreement between these two assays (1, 1). In contrast, the concordance was moderate when HerpeSelect positivity included index values between >1.1 and.. However, we found that % (/) of sero-discordant samples were associated with detection of genital HSV- DNA, and 1% of samples with low-positive HerpeSelect index values could be classified as having established HSV- infection, when results of molecular testing or seroconcordance were included. Overall, nearly % of the study population with positive HerpeSelect serology had index values comprised between >1.1 and., % of whom had evidence of genital HSV- infection. This is consistent with data published by Ashley-Morrow et al showing that % of US patients with established HSV- infection had low HerpeSelect index values (). Reciprocally, 1% of HerpeSelect positive women with genital HSV- DNA had low HerpeSelect index values. These findings demonstrate that a - -

10 non-negligible proportion of true genital herpes cases would be missed when using only a higher cut-off for HerpeSelect The analysis of the kinetics of HSV- antibodies in sera associated with non-primary first clinical episodes of HSV- showed that HerpeSelect detected HSV- seroconversion more frequently and earlier than Kalon, and that HerpeSelect index values increased rapidly. These results corroborate data from Ashley-Morrow et al () demonstrating that in newly infected patients, HerpeSelect index values start low, often in the negative range, and peak a median of weeks later. Our results also confirm the higher sensitivity of HerpeSelect compared with Kalon in detecting non-primary first HSV- episode as previously reported (1). In a US study including 1 patients with non-primary first episodes with culture positive HSV- lesions, the sensitivity of HerpeSelect was % vs. % for Kalon, and the median time for seroconversion was significantly longer by Kalon (1 days) than by HerpeSelect ( days) (1). In our study, patients with non-primary first episodes of HSV- presented to the clinics after a median of days (range -1 days) following symptom onset, thus maximum follow-up time to assess seroconversion was days post onset, which explains the higher detection rate obtained with HerpeSelect. We also found that HerpeSelect seropositivity and index values correlated with reported GUD symptoms in the past year. These results suggest that frequent viral reactivations may sustain specific humoral responses, and, conversely, that low titers may be related to insufficient antigenic stimulation secondary to infrequent viral replication, as suggested by Ashley-Morrow et al. (). Thus, the ability of methods to detect early HSV- infection may account for some of the assay discrepancies found in our and other studies. It is even possible that some of the recent HSV- infections may have been accompanied by a lack of HSV- DNA detection, since the delay between onset of symptoms and presentation at the clinic for study enrollment was quite long for some women, allowing some patients to have already cleared - -

11 the virus. Such misclassifications would have contributed to underestimating the true sensitivity of HerpeSelect We did not use the reference Western blot (WB) HSV assay in this study to help resolve some of the assays discrepancies. However, it has been shown that, although highly sensitive and specific, WB may have less ability to detect recent cases of genital herpes as seroconversion among first episodes of genital HSV- was slower compared to HerpeSelect (1). Moreover, it has been shown that some discordant results between HerpeSelect and WB on African sera were eventually classified as true positive by HerpeSelect after testing with an inhibition assay (). Finally, our data did not support a differential performance of HerpeSelect according to HIV serostatus. By contrast, we observed less discrepancy between HerpeSelect and Kalon in samples from HIV-infected women. This may be related to the higher rate of HSV- reactivation in such patients, which might sustain index values of HSV- specific antibodies in the high range. Our results confirm that some of the low-positive HerpeSelect index values correspond to true HSV- infection and that some may be related to recent infection. Depending on population composition, this would affect the evaluation of the performance of the various HSV- serological assays, and this has to be taken into consideration in the interpretation of study findings. Moreover, the choice of HSV- serological assays would have to be dictated by circumstances, whether for an epidemiological study examining risk factors for HSV- or a clinical trial seeking to enroll HSV- seropositive patients, for which highly specific assays would be more desirable, or for the diagnosis and management of patients with possible early HSV- infection, for which a sensitive assay would be required. Our results have particular resonance for the management of GUD in countries where HSV- infection is highly prevalent and where clinical or sub-clinical primary infection may occur frequently. The - -

12 use of a sensitive assay comparable to HerpeSelect may help to detect recent herpes infection and offer appropriate advice on management and counseling about the risk of HIV acquisition, which could increase in the presence of recent HSV- infection (, 1)

13 Composition of the ANRS 1-1 Study Group Thomas Agyarko-Poku, Comfort Asamoah-Adu, Laurent Bélec 1, Hicham Bouhlal 1, Cécile Chemin 1, Sylvie Deslandes, Agnes Dzokoto, Eric Frost, Gérard Grésenguet, Richard Hayes, Nzambi Khonde, Jérôme LeGoff 1, Jean-De-Dieu Longo, David Mabey, Jean-Elie Malkin, Philippe Mayaud, Jacques Pépin, Ali Si-Mohamed 1, Helen A. Weiss 1 Université Paris V, Equipe «Immunité et Biothérapie Muqueuse», Unité INSERM Internationale U («Immunologie Humaine»), Centres de Recherches Biomédicales des Cordeliers ; and Laboratoire de Virologie, Hôpital Européen Georges Pompidou, Paris, France Clinical Research Unit, Department of Infectious and Tropical Diseases; and Infectious Diseases Epidemiology Unit, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK Centre National de Référence des Maladies Sexuellement Transmissibles et du SIDA de Bangui ; and Unité de Recherches et d Intervention sur les Maladies Sexuellement Transmissibles et du SIDA, Faculté des Sciences de la Santé, Bangui, Central African Republic West African Project To Combat AIDS and STDs, Accra, Ghana Centre for International Health, University of Sherbrooke, Sherbrooke, Canada Centre Médical, Institut Pasteur, Paris, France - 1 -

14 References 1. Ashley-Morrow, R., E. Krantz, and A. Wald.. Time course of seroconversion by HerpeSelect ELISA after acquisition of genital herpes simplex virus type 1 (HSV- 1) or HSV-. Sex Transm Dis :-.. Ashley-Morrow, R., J. Nollkamper, N. J. Robinson, N. Bishop, and J. Smith.. Performance of focus ELISA tests for herpes simplex virus type 1 (HSV-1) and HSV- antibodies among women in ten diverse geographical locations. Clin Microbiol Infect :-.. Ashley Morrow, R., E. Krantz, D. Friedrich, and A. Wald.. Clinical correlates of index values in the focus HerpeSelect ELISA for antibodies to herpes simplex virus type (HSV-). J Clin Virol :-.. Brown, J. M., A. Wald, A. Hubbard, K. Rungruengthanakit, T. Chipato, S. Rugpao, F. Mmiro, D. D. Celentano, R. S. Salata, C. S. Morrison, B. A. Richardson, and N. S. Padian.. Incident and prevalent herpes simplex virus type infection increases risk of HIV acquisition among women in Uganda and Zimbabwe. AIDS 1:-1.. Carter, J., F. J. Bowden, K. S. Sriprakash, I. Bastian, and D. J. Kemp. 1. Diagnostic polymerase chain reaction for donovanosis. Clin Infect Dis :-.. Gorander, S., J. Mbwana, E. Lyamuya, T. Lagergard, and J. A. Liljeqvist.. Mature glycoprotein g presents high performance in diagnosing herpes simplex virus type infection in sera of different tanzanian cohorts. Clin Vaccine Immunol 1:-.. Hogrefe, W., X. Su, J. Song, R. Ashley, and L. Kong.. Detection of herpes simplex virus type -specific immunoglobulin G antibodies in African sera by using recombinant gg, Western blotting, and gg inhibition. J Clin Microbiol :-.. Johnson, G., S. Nelson, M. Petric, and R. Tellier.. Comprehensive PCR-based assay for detection and species identification of human herpesviruses. J Clin Microbiol :-.. Laeyendecker, O., C. Henson, R. H. Gray, R. H. Nguyen, B. J. Horne, M. J. Wawer, D. Serwadda, N. Kiwanuka, R. A. Morrow, W. Hogrefe, and T. C. Quinn.. Performance of a commercial, type-specific enzyme-linked immunosorbent assay for detection of herpes simplex virus type -specific antibodies in Ugandans. J Clin Microbiol :

15 Legoff, J., H. Bouhlal, G. Gresenguet, H. Weiss, N. Khonde, H. Hocini, N. Desire, A. Si-Mohamed, J. de Dieu Longo, C. Chemin, E. Frost, J. Pepin, J. E. Malkin, P. Mayaud, and L. Belec.. Real-time PCR quantification of genital shedding of herpes simplex virus (HSV) and human immunodeficiency virus (HIV) in women coinfected with HSV and HIV. J Clin Microbiol :-.. Legoff, J., H. A. Weiss, G. Gresenguet, K. Nzambi, E. Frost, R. J. Hayes, D. C. Mabey, J. E. Malkin, P. Mayaud, and L. Belec.. Cervicovaginal HIV-1 and herpes simplex virus type shedding during genital ulcer disease episodes. AIDS 1: Morrow, R. A., D. Friedrich, and E. Krantz.. Performance of the focus and Kalon enzyme-linked immunosorbent assays for antibodies to herpes simplex virus type glycoprotein G in culture-documented cases of genital herpes. J Clin Microbiol 1: Nascimento, M. C., S. Ferreira, E. Sabino, I. Hamilton, J. Parry, C. S. Pannuti, and P. Mayaud.. Performance of the HerpeSelect (Focus) and Kalon Enzyme- Linked Immunosorbent Assays for Detection of Antibodies against Herpes Simplex Virus Type by Use of Monoclonal Antibody-Blocking Enzyme Immunoassay and Clinicovirological Reference Standards in Brazil. J Clin Microbiol :-. 1. Orle, K. A., C. A. Gates, D. H. Martin, B. A. Body, and J. B. Weiss. 1. Simultaneous PCR detection of Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus types 1 and from genital ulcers. J Clin Microbiol :-. 1. Reynolds, S. J., A. R. Risbud, M. E. Shepherd, J. M. Zenilman, R. S. Brookmeyer, R. S. Paranjape, A. D. Divekar, R. R. Gangakhedkar, M. V. Ghate, R. C. Bollinger, and S. M. Mehendale.. Recent herpes simplex virus type infection and the risk of human immunodeficiency virus type 1 acquisition in India. J Infect Dis 1: van Dyck, E., A. Buve, H. A. Weiss, J. R. Glynn, D. W. Brown, B. De Deken, J. Parry, and R. J. Hayes.. Performance of commercially available enzyme immunoassays for detection of antibodies against herpes simplex virus type in African populations. J Clin Microbiol :

16 Table 1. Distribution of HerpeSelect gg index values according to genital HSV- DNA detection in women with genital ulcer disease in Ghana and the Central African Republic HerpeSelect index values Genital HSV- DNA 1 <. (Negative). 1.1 (Equivocal) >1.1. (Low positive) >. (High positive) Total N= N= N= N= N= Negative (%) (%) (%) 1 (1%) 1 (%) Positive (%) 1 (%) (%) 1 (%) (%) History of GUD in (1%) 1 (1%) 1 (%) 1 (%) (%) past 1 months 1 Defined as presence of lesional and/or cervico-vaginal HSV- DNA by real-time PCR. PCR result undetermined for,, and patients in respective HerpeSelect groups <.,.-1.1, >1.1-., and >., i.e. 1 in Total. PCR result undetermined for 1 sample in each group, i.e. patients in Total

17 Table. Results of HerpeSelect and Kalon testing according to assay index values. Number (%) of women HerpeSelect Index Values * Kalon Index Values >1.1 **.-1.1 HSV- DNA pos HSV- DNA neg HSV- DNA pos HSV- DNA neg <. *** HSV- DNA pos HSV- DNA neg >. > <. (%) 1 1 (1%) 1 (%) (%) 1 1 (%) Total (n=1) 1 (%) * Sera with HerpeSelect equivocal values of.-1.1 were excluded from this analysis ** HSV DNA data missing for 1 sample from group with HerpeSelect >1.1-. *** HSV DNA data missing for samples from group with HerpeSelect >1.1-. and 1 sample from group with HerpeSelect <

18 Legend for the figure Number of cases and timing of HSV- seroconversion by HSV- serological assay, among 1 patients with first episode of genital HSV- in Ghana and the Central African Republic. At day 1, 1 women were tested. At day the number of seroconversion cases corresponds to the cumulative number of seroconverters of days 1 and. Results of HerpeSelect are presented in black bars and results of Kalon in grey bars. Figure Number of seroconverters HerpeSelect Kalon Day 1 Day - 1 -