Aetiology of genital ulcer disease in female partners of male participants in a circumcision trial in Uganda

The global and regional burden of genital ulcer disease due to herpes simplex virus: a natural history modelling study

Introduction

Herpes simplex virus (HSV) infection can cause painful, recurrent genital ulcer disease (GUD), which can have a substantial impact on sexual and reproductive health. HSV-related GUD is most often due to HSV type 2 (HSV-2), but may also be due to genital HSV type 1 (HSV-1), which has less frequent recurrent episodes than HSV-2. The global burden of GUD has never been quantified. Here we present the first global and regional estimates of GUD due to HSV-1 and HSV-2 among women and men aged 15-49 years old.

Methods

We developed a natural history model reflecting the clinical course of GUD following HSV-2 and genital HSV-1 infection, informed by a literature search for data on model parameters. We considered both diagnosed and undiagnosed symptomatic infection. This model was then applied to existing infection estimates and population sizes for 2016. A sensitivity analysis was carried out varying the assumptions made.

Results

We estimated that 187 million people aged 15-49 years had at least one episode of HSV-related GUD globally in 2016: 5.0% of the world's population. Of these, 178 million (95% of those with HSV-related GUD) had HSV-2 compared with 9 million (5%) with HSV-1. GUD burden was highest in Africa, and approximately double in women compared with men. Altogether there were an estimated 8 billion person-days spent with HSV-related GUD globally in 2016, with 99% of days due to HSV-2. Taking into account parameter uncertainty, the percentage with at least one episode of HSV-related GUD ranged from 3.2% to 7.9% (120-296 million). However, the estimates were sensitive to the model assumptions.

Conclusion

Our study represents a first attempt to quantify the global burden of HSV-related GUD, which is large. New interventions such as HSV vaccines, antivirals or microbicides have the potential to improve the quality of life of millions of people worldwide.

Critical evaluation of arguments opposing male circumcision: A systematic review

OBJECTIVE

To systematically evaluate evidence against male circumcision (MC).

METHODS

We searched PubMed, Google Scholar, EMBASE and Cochrane databases.

RESULTS

Database searches retrieved 297 publications for inclusion. Bibliographies of these yielded 101 more. After evaluation we found: Claims that MC carries high risk were contradicted by low frequency of adverse events that were virtually all minor and easily treated with complete resolution. Claims that MC causes psychological harm were contradicted by studies finding no such harm. Claims that MC impairs sexual function and pleasure were contradicted by high-quality studies finding no adverse effect. Claims disputing the medical benefits of MC were contradicted by a large body of high-quality evidence indicating protection against a wide range of infections, dermatological conditions, and genital cancers in males and the female sexual partners of men. Risk-benefit analyses reported that benefits exceed risks by 100-200 to 1. To maximize benefits and minimize risks, the evidence supported early infant MC rather than arguments that the procedure should be delayed until males are old enough to decide for themselves. Claims that MC of minors is unethical were contradicted by balanced evaluations of ethical issues supporting the rights of children to be provided with low-risk, high-benefit interventions such as MC for better health. Expert evaluations of case-law supported the legality of MC of minors. Other data demonstrated that early infant MC is cost-saving to health systems.

CONCLUSIONS

Arguments opposing MC are supported mostly by low-quality evidence and opinion, and are contradicted by strong scientific evidence.

Herpes simplex virus type 1 epidemiology in Africa: Systematic review, meta-analyses, and meta-regressions

OBJECTIVE

To assess herpes simplex virus type 1 (HSV-1) epidemiology in Africa.

METHODS

This systematic review was conducted per the Cochrane Collaboration guidelines. Findings were reported following the PRISMA guidelines. Research questions were addressed using random-effects meta-analyses and meta-regressions.

RESULTS

Forty-three overall (and 69 stratified) HSV-1 seroprevalence measures, and 18 and eight proportions of HSV-1 viral detection in genital ulcer disease (GUD) and in genital herpes, respectively, were extracted from 37 reports. Pooled mean seroprevalence was 67.1% (95% confidence interval (CI): 54.7-78.5%) in children, and 96.2% (95% CI: 95.0-97.3%) in adults. Across age groups, pooled mean was 44.4% (95% CI: 29.9-59.3%) in ≤5 years-old, 85.6% (95% CI: 81.0-89.6%) in 6-15 years-old, 93.3% (95% CI: 89.2-96.6%) in 16-25 years-old, and 93.8% (95% CI: 84.6-99.4%) in >25 years-old. Age explained 78.8% of seroprevalence variation. Pooled mean proportion of HSV-1 detection was 0.4% (95% CI: 0.0-1.5%) in GUD, and 1.2% (95% CI: 0.0-4.0%) in genital herpes.

CONCLUSIONS

HSV-1 is universally prevalent in Africa, at higher levels than other regions, with no evidence for declines in seroprevalence in recent decades. Nearly every person acquires the infection in childhood through oral-to-oral transmission, before sexual debut. Sexual oral-to-genital and genital-to-genital transmission appear very limited.

Does Male Circumcision Reduce Women's Risk of Sexually Transmitted Infections, Cervical Cancer, and Associated Conditions?

Background: Male circumcision (MC) is proven to substantially reduce men's risk of a number of sexually transmitted infections (STIs). We conducted a detailed systematic review of the scientific literature to determine the relationship between MC and risk of STIs and associated conditions in women. Methods: Database searches by "circumcision women" and "circumcision female" identified 68 relevant articles for inclusion. Examination of bibliographies of these yielded 14 further publications. Each was rated for quality using a conventional rating system. Results: Evaluation of the data from the studies retrieved showed that MC is associated with a reduced risk in women of being infected by oncogenic human papillomavirus (HPV) genotypes and of contracting cervical cancer. Data from randomized controlled trials and other studies has confirmed that partner MC reduces women's risk not only of oncogenic HPV, but as well Trichomonas vaginalis, bacterial vaginosis and possibly genital ulcer disease. For herpes simplex virus type 2, Chlamydia trachomatis, Treponema pallidum, human immunodeficiency virus and candidiasis, the evidence is mixed. Male partner MC did not reduce risk of gonorrhea, Mycoplasma genitalium, dysuria or vaginal discharge in women. Conclusion: MC reduces risk of oncogenic HPV genotypes, cervical cancer, T. vaginalis, bacterial vaginosis and possibly genital ulcer disease in women. The reduction in risk of these STIs and cervical cancer adds to the data supporting global efforts to deploy MC as a health-promoting and life-saving public health measure and supplements other STI prevention strategies.

Interplay among Vaginal Microbiome, Immune Response and Sexually Transmitted Viral Infections

The vaginal ecosystem is important for women's health and for a successful reproductive life, and an optimal host-microbial interaction is required for the maintenance of eubiosis. The vaginal microbiota is dominated by Lactobacillus species in the majority of women. Loss of Lactobacillus dominance promotes the colonization by anaerobic bacterial species with an increase in microbial diversity. Vaginal dysbiosis is a very frequent condition which affects the immune homeostasis, inducing a rupture in the epithelial barrier and favoring infection by sexually transmitted pathogens. In this review, we describe the known interactions among immune cells and microbial commensals which govern health or disease status. Particular attention is given to microbiota compositions which, through interplay with immune cells, facilitate the establishment of viral infections, such as Human Immunodeficiency Virus (HIV), Human Papilloma Virus (HPV), Herpes Simplex Virus 2 (HSV2).

Trends in the relative prevalence of genital ulcer disease pathogens and association with HIV infection in Johannesburg, South Africa, 2007-2015

Background

In South Africa, treatment of genital ulcer disease (GUD) occurs in the context of syndromic management. GUD aetiological studies have been conducted in Johannesburg since 2007. We report on GUD pathogen prevalence, sero-prevalence of STI co-infections and aetiological trends among GUD patients presenting to a community-based primary healthcare facility in Johannesburg over a 9-year period.

Methods and findings

GUD surveys were conducted from January to April each year. Consecutive genital ulcers were sampled from consenting adults. Swab-extracted DNA was tested by multiplex real-time PCR assays for herpes simplex virus (HSV), Treponema pallidum (TP), Haemophilus ducreyi (HD) and Chlamydia trachomatis (CT). HSV-positive DNA extracts were further subtyped into HSV-1 and HSV-2 using a commercial PCR assay; CT-positive extracts were tested with an in-house PCR assay specific for serovars L1-L3 (lymphogranuloma venereum). Sera were tested for HIV, HSV-2, and syphilis co-infections. Giemsa-stained ulcer smears were screened for Klebsiella granulomatis by microscopy. Data were analysed with STATA^TM version 14. Of 771 GUD specimens, 503 (65.2%) had a detectable pathogen: HSV 468 (60.7%); TP 30 (3.9%); CT L1-3 7 (0.9%); HD 4 (0.5%). No aetiological agents were detected in 270 (34.8%) ulcer specimens. Seroprevalence rates were as follows: HIV 61.7%; HSV-2 80.2% and syphilis 5.8%. There was a strong association between GUD pathogen detection and HIV seropositivity (p < 0.001); 68% of cases caused by HSV were co-infected with HIV. There was a significant decline in the relative prevalence of ulcer-derived HSV over time, predominantly from 2013–2015 (p-value for trend = 0.023); and a trend towards a decrease in the HIV seropositivity rate (p-value for trend = 0.209).

Conclusions

HSV remains the leading cause of pathogen-detectable GUD in South Africa. The prevalence of HIV co-infection among GUD patients is high, underlining the importance of linkage to universal HIV testing and treatment in primary healthcare settings.

Association between male circumcision and women's biomedical health outcomes: a systematic review

BACKGROUND

Male circumcision reduces men's risk of acquiring HIV and some sexually transmitted infections from heterosexual exposure, and is essential for HIV prevention in sub-Saharan Africa. Studies have also investigated associations between male circumcision and risk of acquisition of HIV and sexually transmitted infections in women. We aimed to review all evidence on associations between male circumcision and women's health outcomes to benefit women's health programmes.

METHODS

In this systematic review we searched for peer-reviewed and grey literature publications reporting associations between male circumcision and women's health outcomes up to April 11, 2016. All biomedical (not psychological or social) outcomes in all study types were included. Searches were not restricted by year of publication, or to sub-Saharan Africa. Publications without primary data and not in English were excluded. We extracted data and assessed evidence on each outcome as high, medium, or low consistency on the basis of agreement between publications; outcomes found in fewer than three publications were indeterminate consistency.

FINDINGS

60 publications were included in our assessment. High-consistency evidence was found for five outcomes, with male circumcision protecting against cervical cancer, cervical dysplasia, herpes simplex virus type 2, chlamydia, and syphilis. Medium-consistency evidence was found for male circumcision protecting against human papillomavirus and low-risk human papillomavirus. Although the evidence shows a protective association with HIV, it was categorised as low consistency, because one trial showed an increased risk to female partners of HIV-infected men resuming sex early after male circumcision. Seven outcomes including HIV had low-consistency evidence and six were indeterminate.

INTERPRETATION

Scale-up of male circumcision in sub-Saharan Africa has public health implications for several outcomes in women. Evidence that female partners are at decreased risk of several diseases is highly consistent. Synergies between male circumcision and women's health programmes should be explored.

FUNDING

US Centers for Disease Control and Prevention and Jhpiego.

Highly conserved intragenic HSV-2 sequences: Results from next-generation sequencing of HSV-2 UL and US regions from genital swabs collected from 3 continents

INTRODUCTION

Understanding the variability in circulating herpes simplex virus type 2 (HSV-2) genomic sequences is critical to the development of HSV-2 vaccines.

METHODS

Genital lesion swabs containing ≥ 107log10 copies HSV DNA collected from Africa, the USA, and South America underwent next-generation sequencing, followed by K-mer based filtering and de novo genomic assembly. Sites of heterogeneity within coding regions in unique long and unique short (UL_US) regions were identified. Phylogenetic trees were created using maximum likelihood reconstruction.

RESULTS

Among 46 samples from 38 persons, 1468 intragenic base-pair substitutions were identified. The maximum nucleotide distance between strains for concatenated UL_US segments was 0.4%. Phylogeny did not reveal geographic clustering. The most variable proteins had non-synonymous mutations in < 3% of amino acids.

CONCLUSIONS

Unenriched HSV-2 DNA can undergo next-generation sequencing to identify intragenic variability. The use of clinical swabs for sequencing expands the information that can be gathered directly from these specimens.

A transmission-virulence evolutionary trade-off explains attenuation of HIV-1 in Uganda

Evolutionary theory hypothesizes that intermediate virulence maximizes pathogen fitness as a result of a trade-off between virulence and transmission, but empirical evidence remains scarce. We bridge this gap using data from a large and long-standing HIV-1 prospective cohort, in Uganda. We use an epidemiological-evolutionary model parameterised with this data to derive evolutionary predictions based on analysis and detailed individual-based simulations. We robustly predict stabilising selection towards a low level of virulence, and rapid attenuation of the virus. Accordingly, set-point viral load, the most common measure of virulence, has declined in the last 20 years. Our model also predicts that subtype A is slowly outcompeting subtype D, with both subtypes becoming less virulent, as observed in the data. Reduction of set-point viral loads should have resulted in a 20% reduction in incidence, and a three years extension of untreated asymptomatic infection, increasing opportunities for timely treatment of infected individuals.

Pros and cons of circumcision: an evidence-based overview

Based on three large randomized controlled trials (RCTs) conducted in Africa, it can clearly be stated that circumcision lowers the risk of infection with the human immunodeficiency virus (HIV) and some sexually transmitted infections (STIs) among males in settings of high HIV and STI endemicity. Similar effects on STI risk may exist for females, although this may result from an indirect effect of decreasing risk of infection among male partners. It is unknown whether circumcision prevents HIV acquisition in men who have sex with men (MSM), although there might be a protective effect for men who engage mainly in insertive anal intercourse. When the effects of adult circumcision on sexual function and satisfaction of men are examined, high-quality evidence strongly supports lack of harm. Whether circumcision alters sexual satisfaction of female partners is not known as fewer and smaller studies reported conflicting results. Circumcision rarely causes serious complications if practiced by trained practitioners, in a sterile setting, and with a proper follow-up. These conclusions are limited by the lack of high-quality data from areas outside of Africa. RCTs have not been conducted to assess the effects of circumcising infants or MSM. Circumcision has well-proven benefits for people residing in areas with high prevalence of STIs, including HIV, and is not unethical for those who choose to be circumcised or have their children circumcised on religious, social, or cultural grounds. For many others, a definite pro or con recommendation, based on a risk-benefit ratio, cannot be made.

Current Concepts for Genital Herpes Simplex Virus Infection: Diagnostics and Pathogenesis of Genital Tract Shedding

Herpes simplex virus 2 (HSV-2) is a DNA virus that is efficiently transmitted through intimate genital tract contact and causes persistent infection that cannot be eliminated. HSV-2 may cause frequent, symptomatic self-limited genital ulcers, but in most persons infection is subclinical. However, recent studies have demonstrated that the virus is frequently shed from genital surfaces even in the absence of signs or symptoms of clinical disease and that the virus can be transmitted during these periods of shedding. Furthermore, HSV-2 shedding is detected throughout the genital tract and may be associated with genital tract inflammation, which likely contributes to increased risk of HIV acquisition. This review focuses on HSV diagnostics, as well as what we have learned about the importance of frequent genital HSV shedding for (i) HSV transmission and (ii) genital tract inflammation, as well as (iii) the impact of HSV-2 infection on HIV acquisition and transmission. We conclude with discussion of future areas of research to push the field forward.

Use of injectable hormonal contraception and women's risk of herpes simplex virus type 2 acquisition: a prospective study of couples in Rakai, Uganda

BACKGROUND

The injectable hormonal contraceptive depo-medroxyprogesterone acetate (DMPA) has been associated with increased risk of HIV acquisition, but findings are inconsistent. Whether DMPA increases the risk of other sexually transmitted viral infections is unknown. We assessed the association between DMPA use and incident herpes simplex virus type 2 (HSV2) infection in women.

METHODS

In this prospective study, we enrolled HIV-negative and HSV2-negative women aged 15-49 years whose HIV-negative male partners were concurrently enrolled in a randomised trial of male circumcision in Rakai, Uganda. We excluded women if either they or their male partners HIV seroconverted. The primary outcome was HSV2 seroconversion, assessed annually. The male circumcision trial was registered with ClinicalTrials.gov, number NCT00425984.

FINDINGS

Between Aug 11, 2003, and July 6, 2006, we enrolled 682 women in this study. We noted HSV2 seroconversions in 70 (10%) women. Incidence was 13·5 per 100 person-years in women consistently using DMPA (nine incident infections per 66·5 person-years), 4·3 per 100 person-years in pregnant women who were not using hormonal contraception (18 incident infections per 423·5 person-years), and 6·6 per 100 person-years in women who were neither pregnant nor using hormonal contraception (35 incident infections per 529·5 person-years). Women consistently using DMPA had an adjusted hazard ratio for HSV2 seroconversion of 2·26 (95% CI 1·09-4·69; p=0·029) compared with women who were neither pregnant nor using hormonal contraception. Of 132 women with HSV2-seropositive partners, seroconversion was 36·4 per 100 person-years in consistent DMPA users (four incident infections per 11 person-years) and 10·7 per 100 person-years in women who were neither pregnant nor using hormonal contraception (11 incident infections per 103 person-years; adjusted hazard ratio 6·23, 95% CI 1·49-26·3; p=0·012).

INTERPRETATION

Consistent DMPA use might increase risk of HSV2 seroconversion; however, study power was low. These findings should be assessed in larger populations with more frequent follow-up than in this study, and other contraceptive methods should also be assessed. Access to a wide range of highly effective contraceptive methods is needed for women, particularly in sub-Saharan Africa.

FUNDING

Bill and Melinda Gates Foundation, Doris Duke Charitable Foundation, US National Institutes of Health, and Fogarty International Center.

Etiology of genital ulcer disease in a sexually transmitted infection reference center in Manaus, Brazilian Amazon

OBJECTIVES

To determine the etiology and factors associated with genital ulcer disease (GUD) among patients presenting to a sexually transmitted infections clinic in Manaus, Brazil; and to compare a multiplex polymerase chain reaction (M-PCR) assay for the diagnosis of GUD with standard methods.

METHODS

Ulcer swabs were collected and used for Tzanck test and processed in an M-PCR to detect herpes simplex virus (HSV-1/2), Treponema pallidum (T. pallidum), and Haemophilus ducreyi (H. ducreyi). Sera were tested for HIV and syphilis antibodies. Multivariable analysis was used to measure the association between clinical aspects and GUD. M-PCR results were compared with syphilis serology and Tzanck tests.

RESULTS

Overall, 434 GUD samples were evaluated, 84.8% from men. DNA from HSV-2 was detected in 55.3% of GUD samples, T. pallidum in 8.3%, HSV-1 in 3.2%, and 32.5% of GUD specimens were negative for the DNA of all three pathogens. No cases of H. ducreyi were identified. HIV serology among GUD patients was 3.2%. Treponemal antibodies and Tzanck test positivity for genital herpes was detected in 25 (5.8%) and in 125 (30.3%) of GUD patients, respectively. In multivariable analysis genital herpes etiology by M-PCR was associated with the vesicular, multiple and recurrent lesions whereas T. pallidum with non-vesicular, non-recurrent lesions. Compared to M-PCR, syphilis serology was 27.8% sensitive and 96.2% specific whereas Tzanck test was 43.8% sensitive and 88.9% specific.

CONCLUSIONS

The predominance of genital herpes etiology suggests a revision of existing national syndromic treatment guidelines in Brazil to include antiherpetic treatment for all GUD patients. The use of M-PCR can significantly improve the diagnosis of GUD and provide a greater sensitivity than standard diagnostics.

Etiologic pattern of genital ulcers in Lusaka, Zambia: has chancroid been eliminated?

BACKGROUND

Genital ulcers are a public health problem in developing countries. The World Health Organization recommends the use of syndromic guidelines for sexually transmitted infection treatment in resource-constrained countries. Monitoring local etiologies provides information that may aid policy for sexually transmitted infection treatment. We investigated the etiology of genital ulcer disease among outpatients in Lusaka, Zambia.

METHODOLOGY

Swabs from genital ulcers of 200 patients were tested using polymerase chain reaction for Treponema pallidum, herpes simplex virus types 1 (HSV-1) and 2 (HSV-2), Haemophilus ducreyi, and Chlamydia trachomatis.

RESULTS

The prevalence of the detected pathogens was as follows; HSV-2, 28%; T. pallidum, 11.5%; C. trachomatis, 3%; HSV-1, 0.5%; and H. ducreyi, 0%. Coinfection with HSV-2 and T. pallidum was 1.5%, and coinfection of HSV-2 and C. trachomatis was 1%. In 55% of the patients, no etiologic diagnosis could be established.

CONCLUSIONS

H. ducreyi was not detected, whereas HSV-2 and T. pallidum were the commonest pathogens. Nondetection of H. ducreyi requires further studies. If the present findings are validated, treatment guidelines would require to be revised in Zambia.

Herpes simplex virus type-2 assay specificity and male circumcision to reduce herpes simplex virus type-2 acquisition

Three male circumcision (MC) trials which enrolled over 10,000 men of different ages, settings (urban vs. rural), countries (Uganda, Kenya and South Africa), and which utilized different surgical techniques were consistent in showing a 51–60% in reduction in HIV incidence [1 –5 ], and all three trials reported that MC decreased high-risk human papillomavirus (HR-HPV) prevalence by 32–35% [6 –8 ].

Circumcision status and incident herpes simplex virus type 2 infection, genital ulcer disease, and HIV infection

OBJECTIVE

We assessed the protective effect of medical male circumcision (MMC) against HIV, herpes simplex virus type 2 (HSV-2), and genital ulcer disease (GUD) incidence.

DESIGN

Two thousand, seven hundred and eighty-seven men aged 18-24 years living in Kisumu, Kenya were randomly assigned to circumcision (n=1391) or delayed circumcision (n=1393) and assessed by HIV and HSV-2 testing and medical examinations during follow-ups at 1, 3, 6, 12, 18, and 24 months.

METHODS

Cox regression estimated the risk ratio of each outcome (incident HIV, GUD, HSV-2) for circumcision status and multivariable models estimated HIV risk associated with HSV-2, GUD, and circumcision status as time-varying covariates.

RESULTS

HIV incidence was 1.42 per 100 person-years. Circumcision was 62% protective against HIV [risk ratio=0.38; 95% confidence interval (CI) 0.22-0.67] and did not change when controlling for HSV-2 and GUD (risk ratio=0.39; 95% CI 0.23-0.69). GUD incidence was halved among circumcised men (risk ratio=0.52; 95% CI 0.37-0.73). HSV-2 incidence did not differ by circumcision status (risk ratio=0.94; 95% CI 0.70-1.25). In the multivariable model, HIV seroconversions were tripled (risk ratio=3.44; 95% CI 1.52-7.80) among men with incident HSV-2 and seven times greater (risk ratio=6.98; 95% CI 3.50-13.9) for men with GUD.

CONCLUSION

Contrary to findings from the South African and Ugandan trials, the protective effect of MMC against HIV was independent of GUD and HSV-2, and MMC had no effect on HSV-2 incidence. Determining the causes of GUD is necessary to reduce associated HIV risk and to understand how circumcision confers protection against GUD and HIV.

The Strong Protective Effect of Circumcision against Cancer of the Penis

Male circumcision protects against cancer of the penis, the invasive form of which is a devastating disease confined almost exclusively to uncircumcised men. Major etiological factors are phimosis, balanitis, and high-risk types of human papillomavirus (HPV), which are more prevalent in the glans penis and coronal sulcus covered by the foreskin, as well as on the penile shaft, of uncircumcised men. Circumcised men clear HPV infections more quickly. Phimosis (a constricted foreskin opening impeding the passage of urine) is confined to uncircumcised men, in whom balanitis (affecting 10%) is more common than in circumcised men. Each is strongly associated with risk of penile cancer. These findings have led to calls for promotion of male circumcision, especially in infancy, to help reduce the global burden of penile cancer. Even more relevant globally is protection from cervical cancer, which is 10-times more common, being much higher in women with uncircumcised male partners. Male circumcision also provides indirect protection against various other infections in women, along with direct protection for men from a number of genital tract infections, including HIV. Given that adverse consequences of medical male circumcision, especially when performed in infancy, are rare, this simple prophylactic procedure should be promoted.

Use of acyclovir for suppression of human immunodeficiency virus infection is not associated with genotypic evidence of herpes simplex virus type 2 resistance to acyclovir: analysis of specimens from three phase III trials

Herpes simplex virus type 2 (HSV-2) is the most common cause of genital ulcer disease and is a cofactor for HIV-1 acquisition and transmission. We analyzed specimens from three separate phase III trials of acyclovir (ACV) for prevention of HIV-1 acquisition and transmission to determine if failure of ACV to interrupt HIV acquisition and transmission was associated with genotypic ACV resistance. Acyclovir (400 mg twice daily) or placebo was provided to HSV-2-infected persons at risk of HIV-1 infection in the Mwanza and HPTN 039 trials and to persons dually infected with HSV-2 and HIV-1 who had an HIV-negative partner in the Partners in Prevention study. We extracted HSV DNA from genital ulcer swabs or cervicovaginal lavage fluids from 68 samples obtained from 64 participants randomized to ACV and sequenced the HSV-2 UL23 gene encoding thymidine kinase. The UL23 sequences were compared with published and unpublished data. Variants were observed in 38/1,128 (3.4%) nucleotide positions in the UL23 open reading frame, with 58% of these encoding amino acid changes. No deletions, insertions, or mutations known to be associated with resistance were detected. Thirty-one of the variants (81.5%) are newly reported, 15 of which code for amino acid changes. Overall, UL23 is highly polymorphic compared to other loci in HSV-2, but no drug resistance mutations were detected that could explain the failure to reduce HIV incidence or to prevent HIV-1 transmission in these studies.