Herpes simplex virus type 2: a key role in HIV incidence

Prevalence and risk factors associated with herpes simplex virus-2 infection in a contemporary cohort of HIV-infected persons in the United States

BACKGROUND

We compared the herpes simplex virus type 2 (HSV-2) seroprevalence in a contemporary HIV cohort with the general US population and determined risk factors for HSV-2 infection among HIV-infected persons.

METHODS

The Study to Understand the Natural History of HIV and AIDS in the Era of Effective Therapy (SUN) Study is a prospective observational cohort of 700 HIV-infected adults enrolled in 4 U.S. cities between 2004 and 2006. At baseline, participants completed a behavioral risk questionnaire and provided specimens for HSV-2 serology. We calculated HSV-2 seroprevalence, standardized by age, gender, and race among HIV-infected persons compared with the general US adult population, using data from the National Health and Nutrition Examination Survey from 2003 to 2006. We examined risk factors associated with HSV-2 infection among HIV-infected persons using multivariate logistic regression.

RESULTS

Among 660 (94%) SUN participants with adequate specimens for HSV-2 serologic testing, 548 (83%) were 20 to 49 years old (median age, 39 years; 77% male; 59% non-Hispanic white; median CD4 count, 470 cells/mm; 74% with HIV RNA viral loads <400 copies/mL). HSV-2 seroprevalence was significantly higher among HIV-infected adults (59.7%, 95% confidence interval: 55.8-63.6) compared with the general US population (19.2%, 95% confidence interval: 17.5-21.1). In multivariate analysis, we found that older age, female gender, black non-Hispanic race/ethnicity, being currently unemployed, high-risk anal HPV infection, and longer duration since HIV diagnosis were associated with significantly higher odds of HSV-2 infection.

CONCLUSION

HSV-2 seroprevalence is 3 times as high among HIV-infected adults as in the general U.S. population. Clinicians should be aware that increased risk for HSV-2 infection was distributed broadly among HIV-infected persons and not limited to those with high-risk sexual behaviors.

The herpes simplex virus type 1 latency associated transcript locus is required for the maintenance of reactivation competent latent infections

Herpes simplex virus (HSV) establishes latent infections in sensory neurons from which it can periodically reactivate and cause recurrent disease and transmission to new hosts. Little is known about the virally encoded mechanisms that influence the maintenance of HSV latent infectious and modulate the frequency of virus reactivation from the latent state. Here, we report that the latency associated transcript locus of HSV-1 is required for long-term maintenance of reactivation competent latent infections.

Prevalence of HIV and sexually transmitted infections among clients of female sex workers in Karnataka, India: a cross-sectional study

BACKGROUND

Studies have demonstrated the significance of commercial sex work in the ongoing transmission of HIV and other sexually transmitted infections (STIs) in India. Clients of female sex workers (FSWs) are thought to be an important bridging population for HIV/STIs. However, there is a lack of information on basic characteristics of sex work clients. This study sought to describe the prevalence of HIV and other STIs, as well as examine the determinants of these pathogens among a sample of clients in south India.

METHODS

Data were from a cross-sectional biological and behavioural survey of FSW clients from six districts in Karnataka State, India. The prevalence of HIV, syphilis, herpes simplex virus type 2 (HSV-2), chlamydia (CT) and gonorrhoea (NG) among clients was examined. Multivariable logistic regression models were used to analyse the socio-demographic, sexual behaviour and sex-work related characteristics related to the prevalence of each pathogen. Sampling weights and appropriate survey methods were utilized in regression models to account for complex sampling design.

RESULTS

The total sample size was 2,745. The average age of clients was 30.4 (SE:0.3). Across the total sample, the prevalence of HIV, HSV-2, syphilis and CT/NG was 5.6%, 28.4%, 3.6% and 2.2%, respectively. The prevalence of HIV/STIs varied substantially across districts, reaching statistical significance for HIV (p<.0001) and CT/NG (p=.005). In multivariable models, duration of paying for commercial sex was associated with increased risk for HIV and HSV-2 (AOR: 1.1; 95%CI: 1.0-1.1, p<.0001). Clients with brothels as a main FSW solicitation site were associated with increased risk of HIV (AOR: 2.4; 95%CI: 1.2-4.7, p=.001), while those frequenting lodges were at increased risk for CT/NG (AOR: 6.3; 95%CI: 1.9-20.6, p=.03). Examining co-infections, clients with HSV-2 infections were at substantially higher risk of being HIV-positive (AOR: 10.4; 95%CI: 6.1-17.7, p<.0001).

CONCLUSIONS

This study fills in important gaps in knowledge regarding clients in southern India. The strong association between HIV and HSV-2 infections highlights the complications in designing effective prevention, intervention and management programs of this well-hidden population.

VP16 serine 375 is a critical determinant of herpes simplex virus exit from latency in vivo

Development of novel prevention and treatment strategies for herpes simplex virus (HSV) mediated diseases is dependent upon an accurate understanding of the central molecular events underlying the regulation of latency and reactivation. We have recently shown that the transactivation function of the virion protein VP16 is a critical determinant in the exit from latency in vivo. HSV-1 strain SJO2 carries a single serine to alanine substitution at position 375 in VP16 which disrupts its interaction with its essential co-activator Oct-1. Here we report that SJO2 is severely impaired in its ability to exit latency in vivo. This result reinforces our prior observations with VP16 transactivation mutant, in1814, in which VP16 interaction with Oct-1 is also disrupted and solidifies the importance of the VP16-Oct-1 interaction in the early steps in HSV-1 reactivation.

The role of coinfections in HIV epidemic trajectory and positive prevention: a systematic review and meta-analysis

OBJECTIVES

Recurrent or persistent coinfections may increase HIV viral load and, consequently, risk of HIV transmission, thus increasing HIV incidence. We evaluated the association between malaria, herpes simplex virus type 2 (HSV-2) and tuberculosis (TB) coinfections and their treatment on HIV viral load.

DESIGN

Systematic review and meta-analysis of the association of malaria, HSV-2 and TB coinfections and their treatment with HIV viral load.

METHODS

PubMed and Embase databases were searched to 10 February 2010 for studies in adults that reported HIV plasma and/or genital viral load by coinfection status or treatment. Meta-analyses were conducted using random-effects models.

RESULTS

Forty-five eligible articles were identified (six malaria, 20 HSV-2 and 19 TB). There was strong evidence of increased HIV viral load with acute malaria [0.67 log(10) copies/ml, 95% confidence interval (CI) 0.15-1.19] and decreased viral load following treatment (-0.37 log(10) copies/ml, 95% CI -0.70 to -0.04). Similarly, HSV-2 infection was associated with increased HIV viral load (0.18 log(10) copies/ml, 95% CI 0.01-0.34), which decreased with HSV suppressive therapy (-0.28 log(10) copies/ml, 95% CI -0.36 to -0.19). Active TB was associated with increased HIV viral load (0.40 log(10) copies/ml, 95% CI 0.13-0.67), but there was no association between TB treatment and viral load reduction (log(10) copies/ml -0.02, 95% CI -0.19 to 0.15).

CONCLUSION

Coinfections may increase HIV viral load in populations where they are prevalent, thereby facilitating HIV transmission. These effects may be reversed with treatment. However, to limit HIV trajectory and optimize positive prevention for HIV-infected individuals pre-antiretroviral therapy, we must better understand the mechanisms responsible for augmented viral load and the magnitude of viral load reduction required, and retune treatment regimens accordingly.

Episodic therapy for genital herpes in sub-saharan Africa: a pooled analysis from three randomized controlled trials

Background

A randomized controlled trial in South Africa found a beneficial effect of acyclovir on genital ulcer healing, but no effect was seen in trials in Ghana, Central African Republic and Malawi. The aim of this paper is to assess whether the variation in impact of acyclovir on ulcer healing in these trials can be explained by differences in the characteristics of the study populations.

Methodology/Principal Findings

Pooled data were analysed to estimate the impact of acyclovir on the proportion of ulcers healed seven days after randomisation by HIV/CD4 status, ulcer aetiology, size and duration before presentation; and impact on lesional HIV-1. Risk ratios (RR) were estimated using Poisson regression with robust standard errors. Of 1478 patients with genital ulcer, most (63%) had herpetic ulcers (16% first episode HSV-2 ulcers), and a further 3% chancroid, 2% syphilis, 0.7% lymphogranuloma venereum and 31% undetermined aetiology. Over half (58%) of patients were HIV-1 seropositive. The median duration of symptoms before presentation was 6 days. Patients on acyclovir were more likely to have a healed ulcer on day 7 (63% vs 57%, RR = 1.08, 95% CI 0.98–1.18), shorter time to healing (p = 0.04) and less lesional HIV-1 RNA (p = 0.03). Small ulcers (<50 mm²), HSV-2 ulcers, first episode HSV-2 ulcers, and ulcers in HIV-1 seropositive individuals responded best but the better effectiveness in South Africa was not explained by differences in these factors.

Conclusions/Significance

There may be slight benefit in adding acyclovir to syndromic management in settings where most ulcers are genital herpes. The stronger effect among HIV-1 infected individuals suggests that acyclovir may be beneficial for GUD/HIV-1 co-infected patients. The high prevalence in this population highlights that genital ulceration in patients with unknown HIV status provides a potential entry point for provider-initiated HIV testing.

Getting research into policy - Herpes simplex virus type-2 (HSV-2) treatment and HIV infection: international guidelines formulation and the case of Ghana

BACKGROUND

Observational epidemiological and biological data indicate clear synergies between Herpes simplex virus type 2 (HSV-2) and HIV, whereby HSV-2 enhances the potential for HIV acquisition or transmission. In 2001, the World Health Organization (WHO) launched a call for research into the possibilities of disrupting this cofactor effect through the use of antiherpetic therapy. A WHO Expert Meeting was convened in 2008 to review the research results. The results of the trials were mostly inconclusive or showed no impact. However, the WHO syndromic management treatment guidelines were modified to include acyclovir as first line therapy to treat genital ulcer disease on the basis of the high prevalence of HSV-2 in most settings, impact and cost-benefit of treatment on ulcer healing and quality of life among patients.

METHODS

This paper examines the process through which the evidence related to HIV-HSV-2 interactions influenced policy at the international level and then the mechanism of international to national policy transfer, with Ghana as a case study. To better understand the context within which national policy change occurs, special attention was paid to the relationships between researchers and policy-makers as integral to the process of getting evidence into policy. Data from this study were then collected through interviews conducted with researchers, program managers and policy-makers working in sexual health/STI at the 2008 WHO Expert Meeting in Montreux, Switzerland, and in Accra, Ghana.

RESULTS

The major findings of this study indicate that investigations into HSV-2 as a cofactor of HIV generated the political will necessary to reform HSV-2 treatment policy. Playing a pivotal role at both the international level and within the Ghanaian policy context were 'policy networks' formed either formally (WHO) or informally (Ghana) around an issue area. These networks of professionals serve as the primary conduit of information between researchers and policy-makers. Donor influence was cited as the single strongest impetus and impediment to policy change nationally.

CONCLUSIONS

Policy networks may serve as the primary driving force of change in both international context and in the case of Ghana. Communication among researchers and policy-makers is critical for uptake of evidence and opportunities may exist to formalize policy networks and engage donors in a productive and ethical way.

The relative contribution of viral and bacterial sexually transmitted infections on HIV acquisition in southern African women in the Methods for Improving Reproductive Health in Africa study

We assess the relative contribution of viral and bacterial sexually transmitted infections (STIs) on HIV acquisition among southern African women in a nested case-control study within the Methods for Improving Reproductive Health in Africa (MIRA) trial. Cases were women with incident HIV infection; controls were HIV-uninfected at the time of case seroconversion selected in a 1 to 3 case to control ratio (risk-set sampling), matched on study site and time of follow-up. Conditional logistic regression models were used to calculate adjusted odds ratios (AORs) and population-attributable fractions (PAF). Among 4948 enrolled women, we analysed 309 cases and 927 controls. The overall HIV incidence rate was 4.0 per 100 women-years. The incidence of HIV infection was markedly higher in women who had prevalent Herpes simplex virus type 2 (HSV-2) (AOR: 2.14; 95% confidence interval [CI]: 1.55–2.96), incident HSV-2 (AOR: 4.43; 95% CI: 1.77–11.05) and incident Neisseria gonorrhoeae (AOR: 6.92; 95% CI: 3.01–15.90). The adjusted PAF of HIV incidence for prevalent HSV-2 was 29.0% (95% CI: 16.8–39.3), for incident HSV-2 2.1% (95% CI: 0.6–3.6) and for incident N. gonorrhoeae 4.1% (95% CI: 2.5–5.8). Women's greatest risk factors for HIV acquisition were incident bacterial and viral STIs. Women-centred interventions aimed at decreasing HIV incidence in young African women need to address these common co-morbid conditions.

Interactions of HIV, other sexually transmitted diseases, and genital tract inflammation facilitating local pathogen transmission and acquisition

Despite several decades of clinical trials assessing the impact of etiological treatment of sexually transmitted diseases (STDs) to decrease HIV acquisition and transmission, almost all of these trials have not proven to be efficacious. Increasing evidence suggests that specific STD treatment alone may not be sufficient to alter the genital tract inflammatory milieu that is created by STDs. This paper examines the associations between STDs and HIV susceptibility and infectiousness, and considers the role of chronic and refractory inflammation to create an environment that potentiates HIV and STD transmission and acquisition by reviewing biological, observational, and clinical trial data.

Herpes simplex virus type 2 associated with HIV infection among New York heterosexuals living in high-risk areas

Herpes simplex virus type 2 (HSV-2) has been shown to increase the risk of sexual human immunodeficiency virus (HIV) transmission. A matched case-control design was used to examine the association between HSV-2 and HIV infection among heterosexuals in 'high-risk areas' (HRAs) in New York City (NYC). We identified NYC HRAs using HIV surveillance data on heterosexual-related adult HIV diagnoses and USA census data on household poverty. Heterosexuals who were socially or geographically linked to an HRA were recruited using respondent-driven sampling. HIV prevalence was 8.6% and HSV-2 prevalence was 80.1%. Only 6% of HIV-positives knew they were infected. HIV-positive cases were matched to HIV-negative controls on gender, race/ethnicity and age, and tested for antibody to HSV-2. In a multivariate model, HIV infection was associated with HSV-2 infection (adjusted odds ratio [AOR] = 3.5, 95% confidence interval 1.1-11.7) and non-HSV-related sexually transmitted infection diagnosis in the previous year (AOR = 2.6, 1.1-6.2). Effective approaches to HIV risk reduction for individuals with HSV-2 remain uncertain, and these are urgently needed in high-risk communities where multiple social, behavioural and biological factors that facilitate HIV infection coexist.

No impact of oral tenofovir disoproxil fumarate on herpes simplex virus shedding in HIV-infected adults

OBJECTIVE

to determine the impact of oral tenofovir as part of combination antiretroviral therapy on asymptomatic herpes simplex virus (HSV) shedding.

DESIGN

observational study of a cohort of HSV, HIV-1 co-infected adults.

METHODS

HSV infection was diagnosed using type-specific serology (HerpeSelect ELISA, Focus Technologies). Asymptomatic HSV, HIV-1 co-infected individuals achieving HIV viral load below 50 copies/ml on antiretroviral therapy self-collected oral, genital and anal swabs daily for 28 days. Refrigerated specimens were dropped off weekly for HSV-1 and HSV-2 testing by polymerase chain reaction (PCR). Shedding rate was calculated as the proportion of days on which HSV PCR was positive.

RESULTS

: Forty co-infected patients were enrolled, of whom 30 were HSV-2 seropositive. Tenofovir was part of the antiretroviral regimen in 22 of 40 (55%) participants overall and 17 of 30 (57%) of HSV-2 infected participants. The median (interquartile range) HSV-2 shedding rate among HSV-2 seropositive participants was low, at 7.1% (0, 14.3) of specimen collection days, and did not differ between tenofovir users and nonusers (P = 0.36). There was no difference in the number of HSV-2 shedders in the tenofovir and nontenofovir groups (59 vs. 46%; P = 0.49). Rates of shedding for HSV-1 alone (P = 0.59), and for either HSV-1 or HSV-2 (P = 0.38), were also similar between tenofovir users and nonusers.

CONCLUSION

although topical tenofovir 1% gel was associated with a significant decrease in HSV-2 acquisition among high-risk women in the recent CAPRISA 004 trial, in these preliminary data we did not observe an impact of oral tenofovir on HSV-2 or HSV-1 shedding rates among HIV, HSV co-infected asymptomatic adults.

Treatment of sexually transmitted infections for HIV prevention: end of the road or new beginning?

Observational and biological data provide compelling evidence of the importance of sexually transmitted infections (STIs) in HIV transmission, but only one of nine intervention trials has shown an effect. This article reviews the observational studies, critically examines the nine randomized controlled trials evaluating the impact of STI treatment interventions on HIV incidence, and discusses implications for HIV prevention policy, programs and future research. The role of other vaginal infections is also briefly considered. In aggregate, the evidence strongly supports the concept that STI treatment prevents HIV infection. However, issues in trial design and conduct, including HIV epidemic phase, STI prevalence, intervention in comparison groups, and power have affected five of the six trials of treatment of curable STIs. In the three herpes intervention trials, antivirals for HSV suppression were insufficiently potent to alleviate persistent genital inflammation in HIV-negative HSV2-positive persons, and the reduction in HIV levels in HIV-positive persons was insufficient to reduce HIV transmission. It is time for a new phase of exploration of how, when, and in whom to include STI control as a key component of HIV prevention, driven by basic research to elucidate the mechanisms by which STIs and vaginal infections facilitate HIV transmission. From a policy perspective, treatment of curable STIs is an essential part of primary healthcare and is a cheap, simple, and effective intervention when appropriately targeted and delivered. It should be promoted as an essential component of HIV control programs in communities in which the burden of STIs is substantial.

Human immunodeficiency virus test-seeking blood donors in a large blood bank in São Paulo, Brazil

BACKGROUND

Persons with human immunodeficiency virus (HIV) risk behaviors are excluded from donation to reduce the risk of transfusion-transmitted infection. Persons donating to be tested for HIV may therefore deny risk behaviors.

STUDY DESIGN AND METHODS

A random sample of donors completed a survey on motivations, knowledge, and attitudes on the screening process. Donors were considered test seekers if they agreed with two statements "I think that blood donation is a good, fast, and anonymous way to get my blood tested" and "I donate to get my test results." This study was conducted from June to November 2006 at the largest blood bank in São Paulo, Brazil.

RESULTS

Of 3061 participants, 208 (7%) were test seekers. They tended to be male and had a lower educational level. They were more likely to have incorrect knowledge about blood safety (e.g., not knowing that a unit can test antibody negative and still transmit infection, 50% vs. 42%, p = 0.02), express dissatisfaction with screening questions (e.g., feeling that important questions were not asked, 14% vs. 5%, p < 0.01), and concur that donors do not answer questions truthfully (e.g., donors have more sexual partners than they admit, 29% vs. 18%, p < 0.01). Test seekers were more likely to believe that it is acceptable to donate blood to get tested for HIV (41% vs. 10%, p < 0.01).

CONCLUSIONS

Test-seeking motivation, coupled with low knowledge of window period risk, is counter to improving blood safety and to donor prevention needs. Donor education needs to be improved along with availability of appropriate HIV counseling and testing.

Contribution of sexually transmitted infections to the sexual transmission of HIV

PURPOSE OF REVIEW

We review recent evidence about the link between sexually transmitted infections (STI) and HIV transmission and consider implications for control programmes.

RECENT FINDINGS

New studies and meta-analyses confirm the association of HIV acquisition and transmission with recent STIs, although there is considerable heterogeneity between organisms and populations. Much of the recent evidence relates to herpes simplex virus type 2 (HSV-2), for which the population-attributable risk percentage (PAR%) for HSV-2 is between 25 and 35 in Africa. Mathematical models show how transmission attributable to STI varies with HIV epidemic phase, and HSV-2 becomes increasingly important as the epidemic matures. HSV-2 suppressive therapy reduces HIV concentrations in plasma and the genital tract in people coinfected with HSV-2, in part due to direct inhibition of HIV reverse transcriptase. Recent trials of HSV-2 suppressive therapy have not shown an impact on the risk of HIV acquisition, nor in controlling transmission from dually infected people to their serodiscordant heterosexual partners.

SUMMARY

Although there is a plausible link between STI and HIV risk, intervention studies continue to be disappointing. This fact does not disprove a causal link, but mechanisms of action and the design and implementation of interventions need to be better understood.

Population level impact of an imperfect prophylactic vaccine for herpes simplex virus-2

BACKGROUND

The continuation of developing Herpes simplex virus type-2 (HSV-2) prophylactic vaccines requires parallel mathematical modeling to quantify the effect on the population of these vaccines.

METHODS

Using mathematical modeling we derived 3 summary measures for the population effect of imperfect HSV-2 vaccines as a function of their efficacies in reducing susceptibility (VES), genital shedding (VEP), and infectivity during shedding (VEI). In addition, we studied the population level effect of vaccine intervention using representative vaccine efficacies.

RESULTS

A vaccine with limited efficacy of reducing shedding frequency (VEP = 10%) and infectivity (VEI = 0%) would need to reduce susceptibility by 75% (VES = 75%) to substantially reduce the sustainability of HSV-2 infection in a population. No reduction in susceptibility would be required to reach this target in a vaccine that decreased shedding by 75% (VES = 0%, VEP = 75%, VEI = 0%). Mass vaccination using a vaccine with imperfect efficacies (VES = 30%, VEP = 75%, and VEI = 0%) in Kisumu, Kenya, in 2010 would decrease prevalence and incidence in 2020 by 7% and 30%, respectively. For lower prevalence settings, vaccination is predicted to have a lower effect on prevalence.

CONCLUSION

A vaccine with substantially high efficacy of reducing HSV-2 shedding frequency would have a desirable effect at the population level. The vaccine's short-term impact in a high prevalence setting in Africa would be a substantial decrease in incidence, whereas its immediate impact on prevalence would be small and would increase slowly over time.

Acyclovir and transmission of HIV-1 from persons infected with HIV-1 and HSV-2

BACKGROUND

Most persons who are infected with human immunodeficiency virus type 1 (HIV-1) are also infected with herpes simplex virus type 2 (HSV-2), which is frequently reactivated and is associated with increased plasma and genital levels of HIV-1. Therapy to suppress HSV-2 reduces the frequency of reactivation of HSV-2 as well as HIV-1 levels, suggesting that suppression of HSV-2 may reduce the risk of transmission of HIV-1.

METHODS

We conducted a randomized, placebo-controlled trial of suppressive therapy for HSV-2 (acyclovir at a dose of 400 mg orally twice daily) in couples in which only one of the partners was seropositive for HIV-1 (CD4 count, > or = 250 cells per cubic millimeter) and that partner was also infected with HSV-2 and was not taking antiretroviral therapy at the time of enrollment. The primary end point was transmission of HIV-1 to the partner who was not initially infected with HIV-1; linkage of transmissions was assessed by means of genetic sequencing of viruses.

RESULTS

A total of 3408 couples were enrolled at 14 sites in Africa. Of the partners who were infected with HIV-1, 68% were women, and the baseline median CD4 count was 462 cells per cubic millimeter. Of 132 HIV-1 seroconversions that occurred after randomization (an incidence of 2.7 per 100 person-years), 84 were linked within couples by viral sequencing: 41 in the acyclovir group and 43 in the placebo group (hazard ratio with acyclovir, 0.92, 95% confidence interval [CI], 0.60 to 1.41; P=0.69). Suppression with acyclovir reduced the mean plasma concentration of HIV-1 by 0.25 log(10) copies per milliliter (95% CI, 0.22 to 0.29; P<0.001) and the occurrence of HSV-2-positive genital ulcers by 73% (risk ratio, 0.27; 95% CI, 0.20 to 0.36; P<0.001). A total of 92% of the partners infected with HIV-1 and 84% of the partners not infected with HIV-1 remained in the study for 24 months. The level of adherence to the dispensed study drug was 96%. No serious adverse events related to acyclovir were observed.

CONCLUSIONS

Daily acyclovir therapy did not reduce the risk of transmission of HIV-1, despite a reduction in plasma HIV-1 RNA of 0.25 log(10) copies per milliliter and a 73% reduction in the occurrence of genital ulcers due to HSV-2. (ClinicalTrials.gov number, NCT00194519.)