Pediatrics and herpes simplex virus vaccines

The potential of currently unavailable herpes virus vaccines

INTRODUCTION

Despite overwhelming experimental work, there are no licensed vaccines against the most frequent Alphaherpesviruses, namely herpes simplex virus 1 and 2 (HSV1 and 2) nor against the Epstein-Barr virus (EBV), a member of the subfamily Gammaherpesvirus.

AREAS COVERED

Since the DNAs of both HSVs reside in the regional sensory ganglia in a latent state (i.e. as circularized episomal molecules), a corresponding vaccine might be useful for immunotherapy rather than for prevention of primary infection. Here we describe the design of a purified subunit vaccine as well as the preparation and efficacy of a recombinant fusion protein consisting of the gD ectodomain from our domestic attenuated HSV1 strain HSZP. The EBV vaccines considered so far, were destined for prevention of infectious mononucleosis (IM) or to prevent formation of EBV related tumors. To design the EBV peptide vaccine, at least 15 carefully selected immunogenic epitopes coming from 12 virus coded proteins were bound to synthetic micro-particle carriers along with a non-specific pathogen recognizing receptor (PRR) stimulating both the T as well as B lymphocytes.

EXPERT COMMENTARY

The efficacy of a novel EBV peptide in the rabbit model was based on criteria such as antibody formation (EA-D detected by ELISA, early and capsid proteins tested by immunoblot), presence of LMP1 antigen and of viral DNA in peripheral white blood cells. Out of 19 peptide combinations used for vaccination, at least 6 showed a satisfactory protective effect.

Protection from herpes simplex virus (HSV)-2 infection with replication-defective HSV-2 or glycoprotein D2 vaccines in HSV-1-seropositive and HSV-1-seronegative guinea pigs

BACKGROUND

A herpes simplex virus (HSV)-2 candidate vaccine consisting of glycoprotein D (gD2) in alum and monophosphoryl lipid A (MPL) reduced genital herpes disease in HSV-1-seronegative women but not in men or HSV-1-seropositive women.

METHODS

To determine the effect of HSV-1 serostatus on effectiveness of different vaccines, we tested gD2 in alum/MPL, gD2 in Freund's adjuvant, and dl5-29 (a replication-defective HSV-2 mutant) in HSV-1-seropositive or HSV-1-seronegative guinea pigs.

RESULTS

In HSV-1-seronegative animals, dl5-29 induced the highest titers of neutralizing antibody, and after vaginal challenge with wild-type virus, dl5-29 resulted in lower rates of vaginal shedding, lower levels of HSV DNA in ganglia, and a trend for less acute and recurrent genital herpes, compared with the gD2 vaccines. In HSV-1-seropositive animals, all 3 vaccines induced similar titers of neutralizing antibodies and showed similar levels of protection against acute and recurrent genital herpes after vaginal challenge with wild-type virus, but dl5-29 reduced vaginal shedding after challenge more than did the gD2 vaccines.

CONCLUSIONS

dl5-29 Is an effective vaccine in both HSV-1-seropositive and HSV-1-seronegative guinea pigs and was superior to gD2 vaccines in reducing virus shedding after challenge in both groups of animals. dl5-29 Might reduce transmission of HSV-2.

Recent advances in management of genital ulcer disease and anogenital warts

Genital ulcer disease (GUD) constitutes a major public health problem. Most of them are the result of sexually transmitted diseases. Genital herpes, syphilis, lymphogranuloma venereum, granuloma venereum, or chancroid are the commonly encountered GUD. The treatment modalities for these disorders have changed with advent and use of drugs such as azithromycin. The treatment modalities differ in patients with HIV disease. Further vaccines for herpes genitalis and human papilloma virus has opened new avenues in management of these diseases. In regions where there are no diagnostic facilities or where the costs of diagnostic tests are prohibitive, syndromic management of GUD is preferred.

Ocular herpes simplex: changing epidemiology, emerging disease patterns, and the potential of vaccine prevention and therapy

PURPOSE

To review the changing epidemiology of herpes simplex virus infection, emerging patterns of herpetic ocular disease, and the challenges and promise of herpes simplex virus vaccine therapy.

DESIGN

Perspective.

METHODS

Literature review.

RESULTS

An epidemic increase in genital herpes simplex type 2 infection is reflected in a 30% increase in HSV-2 antibodies in the United States since 1976. Approximately one in four people in the United States over age 30 is infected with HSV-2. Primary acquisition of herpes simplex type 1 is becoming progressively delayed in many industrialized countries, in contrast to developing nations where the virus is acquired early in life and is ubiquitous. Changes in sexual behavior among young adults have been associated with a recent increase in genital HSV-1 infection, resulting from oral-genital rather than genital-genital contact. Clinical trials of HSV vaccines using selected herpes simplex virus type 2 proteins mixed in adjuvant have shown limited efficacy in seronegative women, but not in men.

CONCLUSIONS

The recent epidemic of genital herpes simplex type 2 infection is likely to result in an increase in neonatal ocular herpes and in delayed cases of acute retinal necrosis syndrome. The increase in genital HSV-1 may lead to industry production of vaccines that contain components of both HSV-1 and HSV-2 targeted toward limiting genital disease and transmission. As newer herpes simplex vaccines become available, ophthalmologists must be vigilant that a boost in immunity against HSV does not have a paradoxical effect in exacerbating break-through cases that develop immune-mediated herpes simplex stromal keratitis.

Ano-genital herpes in children

Many American children and families are affected by child sexual abuse. The diagnosis of sexual abuse is typically made on the basis of the child's history. Objective evidence of sexual abuse, including abnormal physical findings noted on physical examination or the presence of a sexually transmitted disease, are rare. Ano-genital herpes is one of the most common sexually transmitted diseases found in adults. However, is the presence of ano-genital herpes in children evidence of sexual abuse? The link between ano-genital herpes and sexual abuse requires an understanding of viral transmission and typing to properly interpret its significance. Ano-genital herpes in children creates serious medical, social, and legal implications. It is important that primary care providers have an understanding of the appearance, mode of transmission, and diagnostic technique of ano-genital herpes. Implications for practice will provide guidelines for diagnosing, evaluating, and properly managing ano-genital herpes in children.

Predictors of STI vaccine acceptability among parents and their adolescent children

PURPOSE

To identify attitudes and behavioral factors associated with parental intent to vaccinate their adolescent children against sexually transmitted infections (STI) and adolescent intent to accept vaccination for the prevention of STI.

METHODS

In this cross-sectional study, 320 parents and their adolescent children (aged 12-17 years) were recruited from urban adolescent health clinics and private practice pediatric offices to complete audio, computer-assisted self-interviews (A-CASI). Parents and their adolescents were asked about acceptability of gonorrhea, genital herpes, and human immumodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) vaccines. These three items were summed to create an STI vaccine acceptability scale, the primary outcome variable. Potential predictors measured included health beliefs, sociodemographic factors, and health and sexual behaviors.

RESULTS

A substantial majority of parents and their adolescent children rated the three STI vaccines as very acceptable. Parental health beliefs and parental history of STI diagnosis were significant independent predictors of intent to vaccinate adolescent children against STI. Parental intent to vaccinate and having a friend who had engaged in sexual intercourse were significant independent predictors of adolescents' intent to accept STI vaccination.

CONCLUSIONS

The majority of these parents and their adolescent children found STI vaccination very acceptable, suggesting that there will be great interest in these vaccines once they become available. Interventions designed to address parental health beliefs may prove successful at maintaining or increasing interest in STI vaccines. Adolescents are likely to look to their parents for guidance around acceptance of these vaccines, but personal experiences also may play a role.

Genital herpes in adolescents

Herpes simplex virus (HSV) infections occur commonly among adolescents. Most HSV-2 infections are genital, but genital herpes can be caused by either HSV-1 or HSV-2. Weighted means were calculated based on published seroprevalence data on adolescents from the United States and found HSV-1 rates of 53.1 percent for adolescent males and 49.4 percent for adolescent females. The weighted means for HSV-2 was 15 percent for adolescent females and 12 percent for adolescent males. Most individuals who are infected with HSV-2 are unaware of their infection. Healthcare providers of adolescents should consider genital herpes even when an adolescent presents with nonspecific genital symptoms. In this article, we review current recommendations for diagnosis and management and review the psychological sequelae that can be associated with having genital herpes. Finally, we discuss biomedical interventions that are being developed to help reduce the epidemic of HSV and the challenges that these interventions face with regard to implementation.