Sexually Transmitted Bedfellows: Exquisite Association Between HIV and Herpes Simplex Virus Type 2 in 21 Communities in Southern Africa in the HIV Prevention Trials Network 071 (PopART) Study

Effect of dolutegravir on ferritin, iron, and C-reactive protein among people living with HIV and co-infections

Background

Dolutegravir-based antiretroviral therapy (ART) is currently recommended as the preferred first-line ART in many resource-limited settings. However, little is known about the clinical experience of dolutegravir within a context of prevalent co-infections.

Objectives

To assess virological outcomes, and iron, ferritin and C-reactive protein (CRP) levels among people living with HIV (PLWH) and co-infections after initiating or re-initiating dolutegravir-based ART.

Method

This prospective study was conducted between August 2022 and August 2023. Study participants were recruited from an HIV opportunistic infection clinic. Screening for co-infections (syphilis, hepatitis B virus, cytomegalovirus and herpes simplex virus) was performed at baseline, prior to ART initiation. Plasma HIV viral load (VL), CRP, ferritin and iron levels were measured at baseline and at the 6-month follow-up period.

Results

A total of 100 participants (51 women and 49 men) were enrolled in this study. The median age of the participants was 39 years. The prevalence of co-infections was 30%. Prior to ART initiation, participants with co-infections had higher VL, CRP and ferritin, and lower iron levels, compared to those without co-infections (P < 0.001). Following 6 months of ART, CRP and ferritin levels decreased while iron levels increased, regardless of co-infection status. However, CRP and ferritin remained significantly higher in those with co-infections despite similar and high rates of virologic suppression in both groups.

Conclusion

The presence of co-infections in PLWH is associated with higher VL and with chronic inflammation. Ferritin and CRP decreased on dolutegravir-based ART but remained higher in people with co-infections despite similar rates of virologic suppression.

Incidence of herpes simplex virus type 2 positivity among women living with human immunodeficiency virus in South Africa

BACKGROUND

For women living with HIV (WLHIV), co-infection with herpes simplex virus type 2 (HSV-2) causes severe genital ulcers and presents additional challenges for their HIV care. To inform preventive strategies, we aimed to determine the incidence and risk factors of HSV-2 positivity in a prospective cohort of South African women.

METHODS

The CAPRISA 002 study enrolled women at acute HIV infection between 2004 and 2020. HSV-2 testing was conducted by multiplex polymerase chain reaction (PCR) assay on collected vaginal swabs up to twice annually during follow-up. We calculated incidence as the number of new cases per 100 person-years (PYs) and used Cox-proportional-hazard regression to identify factors associated with time-to-HSV-2 PCR positivity.

RESULTS

At enrolment, the median age of 171 women was 24 years, interquartile range (IQR 21-28), and the estimated median days since HIV infection was 42 (IQR 22-65). Of participants tested at enrolment, HSV-2 antibody prevalence was 81.4% (105/129), and 10.6% (12/113) were positive by PCR. Among 147 women with a prior negative HSV-2 PCR diagnosis, we observed 47 new HSV-2 PCR positive cases over 424.4 PYs of follow-up, yielding an incidence rate of 11.1 cases per-100-PYs. HSV-2 PCR positivity incidence was higher among younger women (<25 years: adjusted Hazard Ratio [aHR] = 5.91, 95%CI 3.02-11.6), those with bacterial vaginosis (BV) (Nugent score 7-10: aHR = 2.17, 95%CI 1.15-4.10) and lower CD4 counts (<500 cells/μl: aHR = 2.04, 95%CI 1.08-3.87).

CONCLUSION

After acute HIV infection in women, the incidence of HSV-2 PCR positivity was associated with younger age, BV diagnosis and lower CD4 count.

Population-level analysis of natural control of HIV infection in Zambia and South Africa: HPTN 071 (PopART)

INTRODUCTION

HIV controllers have low viral loads (VL) without antiretroviral treatment (ART). We evaluated viraemic control in a community-randomized trial conducted in Zambia and South Africa that evaluated the impact of a combination prevention intervention on HIV incidence (HPTN 071 [PopART]; 2013-2018).

METHODS

VL and antiretroviral (ARV) drug testing were performed using plasma samples collected 2 years after enrolment for 4072 participants who were HIV positive at the start of the study intervention. ARV drug use was assessed using a qualitative laboratory assay that detects 22 ARV drugs in five drug classes. Participants were classified as non-controllers if they had a VL ≥2000 copies/ml with no ARV drugs detected at this visit. Additional VL and ARV drug testing was performed at a second annual study visit to confirm controller status. Participants were classified as controllers if they had VLs <2000 with no ARV drugs detected at both visits. Non-controllers who had ARV drugs detected at either visit were excluded from the analysis to minimize potential confounders associated with ARV drug access and uptake.

RESULTS

The final cohort included 126 viraemic controllers and 766 non-controllers who had no ARV drugs detected. The prevalence of controllers among the 4072 persons assessed was 3.1% (95% confidence interval [CI]: 2.6%, 3.6%). This should be considered a minimum estimate, since high rates of ARV drug use in the parent study limited the ability to identify controllers. Among the 892 participants in the final cohort, controller status was associated with biological sex (female > male, p = 0.027). There was no significant association between controller status and age, study country or herpes simplex virus type 2 (HSV-2) status at study enrolment.

CONCLUSIONS

To our knowledge, this report presents the first large-scale, population-level study evaluating the prevalence of viraemic control and associated factors in Africa. A key advantage of this study was that a biomedical assessment was used to assess ARV drug use (vs. self-reported data). This study identified a large cohort of HIV controllers and non-controllers not taking ARV drugs, providing a unique repository of longitudinal samples for additional research. This cohort may be useful for further studies investigating the mechanisms of virologic control.

The population impact of herpes simplex virus type 2 (HSV-2) vaccination on the incidence of HSV-2, HIV and genital ulcer disease in South Africa: a mathematical modelling study

BACKGROUND

Evidence suggests HSV-2 infection increases HIV acquisition risk and HIV/HSV-2 coinfection increases transmission risk of both infections. We analysed the potential impact of HSV-2 vaccination in South Africa, a high HIV/HSV-2 prevalence setting.

METHODS

We adapted a dynamic HIV transmission model for South Africa to incorporate HSV-2, including synergistic effects with HIV, to evaluate the impact of: (i) cohort vaccination of 9-year-olds with a prophylactic vaccine that reduces HSV-2 susceptibility; (ii) vaccination of symptomatically HSV-2-infected individuals with a therapeutic vaccine that reduces HSV shedding.

FINDINGS

An 80% efficacious prophylactic vaccine offering lifetime protection with 80% uptake could reduce HSV-2 and HIV incidence by 84.1% (95% Credibility Interval: 81.2-86.0) and 65.4% (56.5-71.6) after 40 years, respectively. This reduces to 57.4% (53.6-60.7) and 42.1% (34.1-48.1) if efficacy is 50%, 56.1% (53.4-58.3) and 41.5% (34.2-46.9) if uptake is 40%, and 29.4% (26.0-31.9) and 24.4% (19.0-28.7) if protection lasts 10 years. An 80% efficacious therapeutic vaccine offering lifetime protection with 40% coverage among symptomatic individuals could reduce HSV-2 and HIV incidence by 29.6% (21.8-40.9) and 26.4% (18.5-23.2) after 40 years, respectively. This reduces to 18.8% (13.7-26.4) and 16.9% (11.7-25.3) if efficacy is 50%, 9.7% (7.0-14.0) and 8.6% (5.8-13.4) if coverage is 20%, and 5.4% (3.8-8.0) and 5.5% (3.7-8.6) if protection lasts 2 years.

INTERPRETATION

Prophylactic and therapeutic vaccines offer promising approaches for reducing HSV-2 burden and could have important impact on HIV in South Africa and other high prevalence settings.

FUNDING

WHO, NIAID.

Impact of universal testing and treatment on sexual risk behaviour and herpes simplex virus type 2: a prespecified secondary outcomes analysis of the HPTN 071 (PopART) community-randomised trial

BACKGROUND

Comprehensive HIV prevention strategies have raised concerns that knowledge of interventions to reduce risk of HIV infection might mitigate an individual's perception of risk, resulting in riskier sexual behaviour. We investigated the prespecified secondary outcomes of the HPTN 071 (PopART) trial to determine whether a combination HIV prevention strategy, including universal HIV testing and treatment, changed sexual behaviour; specifically, we investigated whether there was evidence of sexual risk compensation.

METHODS

HPTN 071 (PopART) was a cluster-randomised trial conducted during 2013-18, in which we randomly assigned 21 communities with high HIV prevalence in Zambia and South Africa (total population, approximately 1 million) to combination prevention intervention with universal antiretroviral therapy (ART; arm A), prevention intervention with ART provided according to local guidelines (universal since 2016; arm B), or standard of care (arm C). The trial included a population cohort of approximately 2000 randomly selected adults (aged 18-44 years) in each community (N=38 474 at baseline) who were followed up for 36 months. A prespecified secondary objective was to evaluate the impact of the PopART intervention compared with standard of care on herpes simplex virus type 2 (HSV-2) and sexual behaviour (N=20 422 completed final visit). Secondary endpoints included differences in sexual risk behaviour measures at 36 months and were assessed using a two-stage method for matched cluster-randomised trials. This trial is registered with ClinicalTrials. gov, number NCT01900977.

FINDINGS

The PopART intervention did not substantially change probability of self-reported multiple sex partners, sexual debut, or pregnancy in women at 36 months. Adjusted for baseline community prevalence, reported condomless sex was significantly lower in arm A versus arm C (adjusted prevalence ratio 0·80 [95% CI 0·64-0·99]; p=0·04) but not in arm B versus arm C (0·94 [0·76-1·17]; p=0·55). 3-year HSV-2 incidence was reduced in arm B versus arm C (adjusted risk ratio 0·76 [95% CI 0·63-0·92]; p=0·010); no significant change was shown between arm A versus arm C (0·89 [0·73-1·08]; p=0·199).

INTERPRETATION

We found little evidence of any change in sexual behaviour owing to the PopART interventions, and reassuringly for public health, we saw no evidence of sexual risk compensation. The findings do not help to explain the differences between the two intervention groups of the HPTN 071 (PopART) trial.

FUNDING

National Institute of Allergy and Infectious Diseases, the National Institutes of Health, the International Initiative for Impact Evaluation (3ie), the Bill & Melinda Gates Foundation, the US President's Emergency Plan for AIDS Relief, and the Medical Research Council UK.

Herpes simplex virus type 2 (HSV-2) and its association with HIV, HCV, HBV, HTLV-1&2 and syphilis among men who have sex with men in Burkina Faso

PURPOSE

This study aimed to estimate herpes simplex virus type 2 (HSV-2) seroprevalence and its association with HIV, HBV, HCV, HTLV-1&2 and syphilis among men who have sex with men (MSM) in Ouagadougou, Burkina Faso, West Africa.

MATERIALS AND METHODS

We screened MSM sera for HSV-2 antibodies. A total of 329 sera were collected from an HIV and syphilis behavioral and biological cross-sectional survey conducted among MSM in Ouagadougou from January to April 2013. Serum samples were tested using Enzyme Linked Immuno-Sorbent Assay (ELISA) for the detection of IgG antibodies to HSV-2. Also, antibodies to HTLV-1&2, HBsAg and anti-HCV antibodies were screened by ELISA. Laboratory assays were performed according to manufacturers' instructions at the Biomedical Research Laboratory at the "Institut de Recherche en Sciences de la Sante" (IRSS) in Burkina Faso.

RESULTS

The seroprevalence of HSV-2 infection among MSM was 14.3%(95% CI: 10.6-18.1), with disparities according to age and occupation. HSV-2 seroprevalence was high among MSM who were seropositive for HIV (40% versus 13.9%), for syphilis (42.9% versus 13.3%), for HCV (32.5% versus 11.7%) and for HTLV-1&2 (38.5% versus 12.9%) compared to people seronegative for these pathogens. Multivariate analysis showed that HIV-positive (ORa ​= ​5.34, p ​= ​0.027), anti-HCV-positive (ORa ​= ​4.44, p ​= ​0.001), and HTLV-1&2 positive (aOR ​= ​4.11, p ​= ​0.046) were associated with HSV-2 infection among MSM. However, no significant statistical association between HSV-2 and syphilis was found.

CONCLUSION

HSV-2 seroprevalence among MSM in Burkina Faso is relatively high. Positive associations between sexual transmitted infections including HIV with HSV-2 suggest that HSV-2 infection's prevention should be strengthened through HIV transmission control programs.

Burden of sexually transmitted infections from acute HIV infection among women in South Africa: Evidence from a prospective cohort study

PURPOSE

HIV and other sexually transmitted infections (STIs) often co-occur. However, less evidence exists on the long-term STI dynamics among persons living with HIV in sub-Saharan Africa to inform interventions. We investigated the incidence, prevalence and factors associated with STIs, starting from acute HIV infection in a cohort of South African women.

METHODS

The CAPRISA002 study enrolled women with acute HIV infection and performed STI testing and treatment 1-2 times annually from 2004-2020. We estimated STI incidence, re-infection, and prevalence trends before and after antiretroviral treatment (ART). We fitted Cox regression models to identify factors associated with STIs.

RESULTS

We followed up 235 women (median age = 25 years, IQR 22-29) for 7.5 years (IQR 5.7-10.8). New STI and re-infection cases per 100 person-years (PYs) were 5.1 and 9.5 for Neisseria gonorrhoeae (NG), 7.4 and 14.7 for Chlamydia trachomatis (CT), 8.0 and 26.6 for Trichomonas vaginalis (TV), 7.7 and 16.7 for Mycoplasma genitalium (MG) and 25.2 and 37.3 for any STI. STI incidence, was associated with HIV log₁₀ viral load (AHR = 1.24, 95% CI 1.06-1.44), active syphilis (AHR = 16.55, 95% CI 7.49-36.55), a positive HSV-2 PCR (AHR = 1.54, 95% CI 1.01-2.35), bacterial vaginosis (AHR = 1.48, 95% CI 1.01-2.18), recent regular sexual partners at enrolment (one vs none: AHR = 2.62, 95% CI 1.41-4.87; two plus vs none: AHR = 3.68, 95% CI 1.79-7.59) and age (5-year fold: AHR = 0.80, 95% CI 0.70-0.92).

CONCLUSION

The persistent STI/HIV co-infection burden among South African women highlights that early HIV diagnosis and ART initiation needs to be combined with better STI care for women and their partners to prevent HIV and STI transmission.

Association of medical male circumcision and sexually transmitted infections in a population-based study using targeted maximum likelihood estimation

Background

Epidemiological theory and many empirical studies support the hypothesis that there is a protective effect of male circumcision against some sexually transmitted infections (STIs). However, there is a paucity of randomized control trials (RCTs) to test this hypothesis in the South African population. Due to the infeasibility of conducting RCTs, estimating marginal or average treatment effects with observational data increases interest. Using targeted maximum likelihood estimation (TMLE), a doubly robust estimation technique, we aim to provide evidence of an association between medical male circumcision (MMC) and two STI outcomes.

Methods

HIV and HSV-2 status were the two primary outcomes for this study. We investigated the associations between MMC and these STI outcomes, using cross-sectional data from the HIV Incidence Provincial Surveillance System (HIPSS) study in KwaZulu-Natal, South Africa. HIV antibodies were tested from the blood samples collected in the study. For HSV-2, serum samples were tested for HSV-2 antibodies via an ELISA-based anti-HSV-2 IgG. We estimated marginal prevalence ratios (PR) using TMLE and compared estimates with those from propensity score full matching (PSFM) and inverse probability of treatment weighting (IPTW).

Results

From a total 2850 male participants included in the analytic sample, the overall weighted prevalence of HIV was 32.4% (n = 941) and HSV-2 was 53.2% (n = 1529). TMLE estimates suggest that MMC was associated with 31% lower HIV prevalence (PR: 0.690; 95% CI: 0.614, 0.777) and 21.1% lower HSV-2 prevalence (PR: 0.789; 95% CI: 0.734, 0.848). The propensity score analyses also provided evidence of association of MMC with lower prevalence of HIV and HSV-2. For PSFM: HIV (PR: 0.689; 95% CI: 0.537, 0.885), and HSV-2 (PR: 0.832; 95% CI: 0.709, 0.975). For IPTW: HIV (PR: 0.708; 95% CI: 0.572, 0.875), and HSV-2 (PR: 0.837; 95% CI: 0.738, 0.949).

Conclusion

Using a TMLE approach, we present further evidence of a protective association of MMC against HIV and HSV-2 in this hyper-endemic South African setting. TMLE has the potential to enhance the evidence base for recommendations that embrace the effect of public health interventions on health or disease outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11705-9.

Seroprevalence of Human Herpesvirus Infections in Newly Diagnosed HIV-Infected Key Populations in Dar es Salaam, Tanzania

Background

Human herpesvirus (HHV) infections can significantly increase the risk of human immunodeficiency virus (HIV) transmission and accelerate disease progression. In the population at high risk of HIV infection, also termed as key populations (female sex workers (FSW), men who have sex with men (MSM), and people who inject drugs (PWID)), and their sexual partners, HHV infections can potentially compromise the efforts to prevent and control HIV infection. Here, we investigated the seroprevalence of HHV infections among HIV-infected key populations in Dar es Salaam, Tanzania. Methodology. We analyzed 262 archived serum samples of HIV-infected key populations from the integrated biobehavioral surveillance (IBBS) study conducted in Dar es Salaam, Tanzania. The enzyme-linked immunosorbent assay was used to determine IgG and IgM titers for cytomegalovirus (CMV) and herpes simplex virus (HSV) types 1 and 2.

Results

The overall seropositivity of HHV IgG was 92% (95% CI: 87.7–95.3%). HHV IgM was not detected in any of the samples. The most seroprevalent coinfection was CMV at 69.1% (181/262), followed by HSV-2 33.2% (87/262) and HSV-1 32.1% (84/262). HSV-2 infection differed by key population groups; it accounted for FSW (46.3%) (p=0.0001) compared to PWID (21.6%) and MSM (22.7%). In contrast, seroprevalence for CMV and HSV-1 was comparable across the key population groups; whereby, CMV was 62%, 75.3%, and 75% and HSV-1 was 26.4%, 39.2%, and 31.8% for FSW, MSM, and PWID, respectively. We also observed that multiple coinfections with CMV-HSV-2 (p=0.042) and CMV-HSV-1-HSV-2 (p=0.006) were significantly associated with key population aged above 40 years.

Conclusion

The IgG seroprevalence of CMV, HSV-1, and HSV-2 was high among HIV-positive key populations. These findings indicate that these individuals are prone to recurrence of HHV infections and may harbor replicating viruses that subsequently may affect HIV disease progression. Therefore, this warrants concerted efforts for integrated HIV and sexually transmitted infection prevention programs targeting key populations.

Sexually Transmitted Infections and Human Immunodeficiency Virus

The human immunodeficiency virus (HIV) and sexually transmitted infections (STIs) are considered epidemics in the United States. Research on the association between STIs and HIV infectiousness and susceptibility has shown that STIs promote HIV acquisition and transmission via mucosal inflammation and ulceration caused by viral or bacterial pathogens. Some of the most common STIs associated with HIV are chlamydia, gonorrhea, syphilis, and herpes simplex virus type 2. STIs are a major cause of morbidity and mortality, particularly if diagnosis or treatment is delayed. Prevention and treatment of both HIV and STIs is essential to ending these associated epidemics.

Herpes simplex virus: global infection prevalence and incidence estimates, 2016

Objective

To generate global and regional estimates for the prevalence and incidence of herpes simplex virus (HSV) type 1 and type 2 infection for 2016.

Methods

To obtain data, we undertook a systematic review to identify studies up to August 2018. Adjustments were made to account for HSV test sensitivity and specificity. For each World Health Organization (WHO) region, we applied a constant incidence model to pooled prevalence by age and sex to estimate the prevalence and incidence of HSV types 1 and 2 infections. For HSV type 1, we apportioned infection by anatomical site using pooled estimates of the proportions that were oral and genital.

Findings

In 2016, an estimated 491.5 million people (95% uncertainty interval, UI: 430.4 million–610.6 million) were living with HSV type 2 infection, equivalent to 13.2% of the world’s population aged 15–49 years. An estimated 3752.0 million people (95% UI: 3555.5 million–3854.6 million) had HSV type 1 infection at any site, equivalent to a global prevalence of 66.6% in 0–49-year-olds. Differing patterns were observed by age, sex and geographical region, with HSV type 2 prevalence being highest among women and in the WHO African Region.

Conclusion

An estimated half a billion people had genital infection with HSV type 2 or type 1, and several billion had oral HSV type 1 infection. Millions of people may also be at higher risk of acquiring human immunodeficiency virus (HIV), particularly women in the WHO African Region who have the highest HSV type 2 prevalence and exposure to HIV.

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.

Tenofovir Gel for Prevention of Herpes Simplex Virus Type 2 Acquisition: Findings From the VOICE Trial

BACKGROUND

Genital infection with herpes simplex virus type 2 (HSV-2) is common and increases risk of human immunodeficiency virus (HIV) transmission and acquisition. Pericoital use of tenofovir (TFV) gel provided protection from HSV-2 acquisition in the CAPRISA 004 study.

METHODS

We measured estimate of effect of vaginal TFV 1% gel in preventing HSV-2 acquisition among women in VOICE, randomized, double-blinded, placebo-controlled trial assessing daily use of oral and vaginal TFV for HIV-1 preexposure prophylaxis. The TFV level in plasma at the first quarterly visit was used as a measure of gel use.

RESULTS

Of 566 participants at risk for HSV-2 acquisition, 532 (94%) had first-quarter plasma TFV and end-of-study HSV-2 serologic data available. Over a follow-up period of 501 person-years, 92 incident cases of HSV-2 acquisition occurred: 77 were in women with no TFV detected in plasma, and 15 occurred in women with TFV detected in plasma (incidence, 20.6 cases/100 person-years [95% confidence interval [CI], 16.2-25.7] vs 11.9 cases/100 person-years [95% CI, 6.6-19.6], respectively). TFV detection in plasma was associated with a trend toward a reduced risk of HSV-2 seroconversion, with an unadjusted hazard ratio (HR) of 0.59 (95% CI, .34-1.02; P = .060) and a HR adjusted for site, age, having ≥2 male sex partners in the past 3 months, use of hormonal contraception, having anal sex in the past 3 months, and HIV status of 0.60 (95% CI, .33-1.08; P = .086).

CONCLUSIONS

Detection of TFV in plasma among TFV gel users was associated with a trend toward a reduced risk of HSV-2 acquisition, after controlling for sexual behavior and HIV-1 acquisition.

Global and regional estimates of the contribution of herpes simplex virus type 2 infection to HIV incidence: a population attributable fraction analysis using published epidemiological data

BACKGROUND

A 2017 systematic review and meta-analysis of 55 prospective studies found the adjusted risk of HIV acquisition to be at least tripled in individuals with herpes simplex virus type 2 (HSV-2) infection. We aimed to assess the potential contribution of HSV-2 infection to HIV incidence, given an effect of HSV-2 on HIV acquisition.

METHODS

We used a classic epidemiological formula to estimate the global and regional (WHO regional) population attributable fraction (PAF) and number of incident HIV infections attributable to HSV-2 infection by age (15-24 years, 25-49 years, and 15-49 years), sex, and timing of HSV-2 infection (established vs recently acquired). Estimates were calculated by incorporating HSV-2 and HIV infection data with pooled relative risk (RR) estimates for the effect of HSV-2 infection on HIV acquisition from a systematic review and meta-analysis. Because HSV-2 and HIV have shared sexual and other risk factors, in addition to HSV-related biological factors that increase HIV risk, we only used RR estimates that were adjusted for potential confounders.

FINDINGS

An estimated 420 000 (95% uncertainty interval 317 000-546 000; PAF 29·6% [22·9-37·1]) of 1·4 million sexually acquired incident HIV infections in individuals aged 15-49 years in 2016 were attributable to HSV-2 infection. The contribution of HSV-2 to HIV was largest for the WHO African region (PAF 37·1% [28·7-46·3]), women (34·8% [23·5-45·0]), individuals aged 25-49 years (32·4% [25·4-40·2]), and established HSV-2 infection (26·8% [19·7-34·5]).

INTERPRETATION

A large burden of HIV is likely to be attributable to HSV-2 infection, even if the effect of HSV-2 infection on HIV had been imperfectly measured in studies providing adjusted RR estimates, potentially because of residual confounding. The contribution is likely to be greatest in areas where HSV-2 is highly prevalent, particularly Africa. New preventive interventions against HSV-2 infection could not only improve the quality of life of millions of people by reducing the prevalence of herpetic genital ulcer disease, but could also have an additional, indirect effect on HIV transmission.

FUNDING

WHO.

Vaccines for Herpes Simplex: Recent Progress Driven by Viral and Adjuvant Immunology

Herpes simplex viruses (HSV) types 1 and 2 are ubiquitous. They both cause genital herpes, occasionally severe disease in the immunocompromised, and facilitate much HIV acquisition globally. Despite more than 60 years of research, there is no licensed prophylactic HSV vaccine and some doubt as to whether this can be achieved. Nevertheless, a previous HSV vaccine candidate did have partial success in preventing genital herpes and HSV acquisition and another immunotherapeutic candidate reduced viral shedding and recurrent lesions, inspiring further research. However, the entry pathway of HSV into the anogenital mucosa and the subsequent cascade of immune responses need further elucidation so that these responses could be mimicked or improved by a vaccine, to prevent viral entry and colonization of the neuronal ganglia. For an effective novel vaccine against genital herpes the choice of antigen and adjuvant may be critical. The incorporation of adjuvants of the vaccine candidates in the past, may account for their partial efficacy. It is likely that they can be improved by understanding the mechanisms of immune responses elicited by different adjuvants and comparing these to natural immune responses. Here we review the history of vaccines for HSV, those in development and compare them to successful vaccines for chicken pox or herpes zoster. We also review what is known of the natural immune control of herpes lesions, via interacting innate immunity and CD4 and CD8 T cells and the lessons they provide for development of new, more effective vaccines.

Herpes Simplex virus type 2 myeloradiculitis with a pure motor presentation in a liver transplant recipient

In this case report, we describe the first PCR-confirmed case of HSV2 myeloradiculitis with a purely motor presentation, occurring in a 68-year-old liver transplant recipient. The patient reported ascending weakness with no sensory nor sphincteric symptoms, thereby resembling acute demyelinating inflammatory neuropathy, or Guillain-Barré syndrome. HSV2 was detected in cerebrospinal fluid by PCR, and the patient was successfully treated with intravenous Acyclovir.

Mechanisms of Immune Control of Mucosal HSV Infection: A Guide to Rational Vaccine Design

Herpes Simplex Virus (HSV) is a highly prevalent sexually transmitted infection that aside from causing cold sores and genital lesions, causes complications in the immunocompromised and has facilitated a large proportion of HIV acquisition globally. Despite decades of research, there is no prophylactic HSV vaccine ready for use in humans, leaving many questioning whether a prophylactic vaccine is an achievable goal. A previous HSV vaccine trial did have partial success in decreasing acquisition of HSV2–promising evidence that vaccines can prevent acquisition. However, there is still an incomplete understanding of the immune response pathways elicited by HSV after initial mucosal infection and how best to replicate these responses with a vaccine, such that acquisition and colonization of the dorsal root ganglia could be prevented. Another factor to consider in the rational design of an HSV vaccine is adjuvant choice. Understanding the immune responses elicited by different adjuvants and whether lasting humoral and cell-mediated responses are induced is important, especially when studies of past trial vaccines found that a sufficiently protective cell-mediated response was lacking. In this review, we discuss what is known of the immune control involved in initial herpes lesions and reactivation, including the importance of CD4 and CD8 T cells, and the interplay between innate and adaptive immunity in response to primary infection, specifically focusing on the viral relay involved. Additionally, a summary of previous and current vaccine trials, including the components used, immune responses elicited and the feasibility of prophylactic vaccines looking forward, will also be discussed.