Herpes zoster and meningitis resulting from reactivation of varicella vaccine virus in an immunocompetent child

Serious neurological adverse events in immunocompetent children and adolescents caused by viral reactivation in the years following varicella vaccination

Serious adverse events following vaccination include medical complications that require hospitalisation. The live varicella vaccine that was approved by the Food and Drug Administration in the United States in 1995 has an excellent safety record. Since the vaccine is a live virus, adverse events are more common in immunocompromised children who are vaccinated inadvertently. This review includes only serious adverse events in children considered to be immunocompetent. The serious adverse event called varicella vaccine meningitis was first reported in a hospitalised immunocompetent child in 2008. When we carried out a literature search, we found 15 cases of immunocompetent children and adolescents with varicella vaccine meningitis; the median age was 11 years. Eight of the children had received two varicella vaccinations. Most of the children also had a concomitant herpes zoster rash, although three did not. The children lived in the United States, Greece, Germany, Switzerland, and Japan. During our literature search, we found five additional cases of serious neurological events in immunocompetent children; these included 4 cases of progressive herpes zoster and one case of acute retinitis. Pulses of enteral corticosteroids as well as a lack of herpes simplex virus antibody may be risk factors for reactivation in immunocompetent children. All 20 children with adverse events were treated with acyclovir and recovered; 19 were hospitalised and one child was managed as an outpatient. Even though the number of neurological adverse events remains exceedingly low following varicella vaccination, we recommend documentation of those caused by the vaccine virus.

Meningitis without Rash after Reactivation of Varicella Vaccine Strain in a 12-Year-Old Immunocompetent Boy

Acute neurologic complications from Varicella-Zoster-Virus reactivation occur in both immunocompromised and immunocompetent patients. In this report, we describe a case of a previously healthy immunocompetent boy who had received two doses of varicella vaccine at 1 and 4 years. At the age of 12 he developed acute aseptic meningitis caused by vaccine-type varicella-zoster-virus without concomitant skin eruptions. VZV-vaccine strain DNA was detected in the cerebrospinal fluid. The patient made a full recovery after receiving intravenous acyclovir therapy. This disease course documents another case of a VZV vaccine-associated meningitis without development of a rash, i.e., a form of VZV infection manifesting as "zoster sine herpete".

Bilateral Ptosis, Zosteriform Rash and Flaccid Bladder in a 10-Year-old boy

We present a case report of a 10-year-old completely immunized boy presenting with a 2-week history of bilateral eyelid drooping, fatigue followed by bladder and bowel paralysis. This was followed by the appearance of a vesicular painful and itchy rash which directed further diagnosis and treatment as it was consistent with a varicella reactivation rash. This case is a very important addition to the current body of literature on varicella-related neurological complications. It outlines that varicella reactivation can present in completely vaccinated, immunocompetent young children as a neurological syndrome affecting the autonomic nervous system primarily and the rash can occur a few weeks later after presentation of the neurological symptoms.

A Case of Aseptic Meningitis Without Skin Rash Caused by Oka Varicella Vaccine

Here, we present a previously healthy adolescent with aseptic meningitis without skin rash caused by varicella vaccine derived from the Oka/Biken strain; the patient received a single dose of varicella vaccine at 1 year of age. Pediatricians should be aware of the potential for reactivation of varicella vaccine derived from the Oka/Biken strain, which can cause aseptic meningitis in vaccinated children even in the absence of a skin rash.

Management of Infectious Emergencies for the Inpatient Dermatologist

Purpose of Review

There are various dermatologic emergencies stemming from bacterial, viral, and fungal etiologies that can present in the inpatient setting. This review summarizes the pathogenesis and diagnosis of infections with cutaneous involvement and highlights new therapies.

Recent Findings

Clindamycin inhibits toxin formation and can be used as an adjunct therapy for the staphylococcal scalded syndrome. Isavuconazole therapy for mucormycosis infection is a less toxic alternative to amphotericin B.

Summary

Diagnosis of these infections is primarily guided by high clinical suspicion and early recognition can prevent dangerous sequelae. Treatment mainstays have been well-established, but there are adjunctive therapies that may potentially benefit the patient.

Herpes Zoster in an Immunocompetent Child without a History of Varicella

Herpes zoster is a relatively rare infectious disease in the pediatric population, as compared with adults, which is due to the reactivation of latent Varicella-Zoster virus. We report a 7-year-old child without any history of varicella, who first experienced skin pain and later presented skin lesions in dermatomal distribution. Finally, the patient was diagnosed with herpes zoster. We aim to emphasize that herpes zoster could occur in immunocompetent children and may be due to the reactivation of the vaccine strain or previous subclinical infection.

Herpes Zoster Meningitis in a Young, Immunocompetent Adult

BACKGROUND

Varicella-zoster virus is typically encountered in the emergency department (ED) in two forms: varicella (chickenpox) in children and zoster (shingles) in older adults. Zoster is infrequently encountered in young, healthy adults, and neurological complications are extremely rare.

CASE REPORT

We describe a case of a previously healthy 36-year-old woman who presented to the ED with fever, nuchal rigidity, and headache 4 days after being diagnosed with herpes zoster and started on oral valacyclovir. Lumbar puncture confirmed herpes zoster meningitis. Despite initiation of antivirals within 48 h of symptom onset, progression to zoster meningitis occurred. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians must be aware that neurological complications of varicella zoster can develop despite initiation of oral antivirals. These patients must be identified in the ED, as admission for intravenous antivirals is indicated.

Primary varicella zoster infection compared to varicella vaccine reactivation associated meningitis in immunocompetent children

We diagnosed varicella zoster virus (VZV) meningitis in a healthy adolescent boy who presented without a rash or fever. We aim to compare VZV reactivation meningitis in children after primary VZV infection and VZV vaccination. We reviewed the literature up until June 2020 using Pubmed/MEDLINE and EMBASE databases using 'varicella zoster', 'meningitis' and 'children' as keywords. Only English articles were included. Twenty-five cases were included in this review. Children who had VZV reactivation meningitis after vaccination were younger (7 ± 3.4 years vs. 11.9 ± 3.6 years, P = 0.0038), had a shorter interval between first exposure to reactivation (5.6 ± 2.9 years vs. 8.8 ± 3.2 years, P = 0.018) and more likely to have a rash (100% vs. 55%, P = 0.04). VZV reactivation meningitis occurs after both primary VZV infection and VZV vaccination. The absence of exanthem, fever or meningism does not rule out VZV meningitis.

Vaccine Oka Varicella Meningitis in Two Adolescents

The live-attenuated varicella vaccine, a routine immunization in the United States since 1995, is both safe and effective. Like wild-type varicella-zoster virus, however, vaccine Oka (vOka) varicella can establish latency and reactivate as herpes zoster, rarely leading to serious disease, particularly among immunocompromised hosts. Previous cases of reactivated vOka resulting in meningitis have been described in young children who received a single dose of varicella vaccine; less is known about vOka reactivation in older children after the 2-dose vaccine series. We present 2 adolescents with reactivated vOka meningitis, 1 immunocompetent and 1 immunocompromised, both of whom received 2 doses of varicella vaccine many years before as children. Pediatricians should be aware of the potential of vOka varicella to reactivate and cause clinically significant central nervous system disease in vaccinated children and adolescents.

Severe and Complicated Varicella and Associated Genotypes 10 Years After Introduction of a One-Dose Varicella Vaccine Program

Background

This national, sentinel prospective study aimed to identify children with severe hospitalized varicella, despite availability of universal 1-dose vaccination since 2005, and determine associations between virus genotypes and disease severity.

Methods

Children with varicella or zoster from 5 Paediatric Active Enhanced Disease Surveillance hospitals were enrolled. Lesions were swabbed for genotyping. Associations with disease severity were analyzed using multiple regression.

Results

From 2007 to 2015, 327 children with confirmed varicella (n = 238) or zoster (n = 89) were enrolled. Two hundred three (62%) were immunocompetent children; including 5 of 8 children who required intensive care unit management. Eighteen percent (36 of 203) of immunocompetent children had been previously vaccinated. Vaccinated children aged >18 months were less likely to have severe disease (9%; 5 of 56) than unvaccinated children (21%; 21 of 100; P = .05). Three of 126 children who had virus genotyping (2 immunocompromised) had varicella (n = 2) or zoster (n = 2) due to the Oka/vaccine strain. European origin clades predominated and were independently associated with more severe disease (odds ratio = 3.2; 95% confidence interval, 1.1- 9.5; P = .04).

Conclusions

Severe hospitalized varicella still occurs with a 1-dose varicella program, although predominantly in unvaccinated children. Most 1-dose vaccine recipients were protected against severe disease. Viral genotyping in complex hospitalized cases is important to assist in monitoring disease due to Oka-vaccine strain.

Genotype analysis of ORF 62 identifies varicella-zoster virus infections caused by a vaccine strain in children

This study was performed to differentiate vaccine-type strains from wild-type strains and determine the genotype of varicella-zoster virus (VZV) in 51 Korean children. A sequencing analysis of ORF 62 identified two cases of herpes zoster caused by the vaccine-type virus, without a previous history of varicella, 22 months and 5 months after VZV vaccination. The wild-type strain was identified in the remaining children. A genotype analysis of ORF 22 amino acids revealed genotype J in all children except one. Genotype E was identified in an infant with varicella imported from Egypt.

Varicella Zoster Virus: A Common Cause of Stroke in Children and Adults

BACKGROUND

Varicella zoster virus (VZV) is a neurotropic, exclusively human herpesvirus. Primary infection causes varicella (chickenpox), after which the virus becomes latent in ganglionic neurons along the entire neuraxis. As cell-mediated immunity to VZV declines with advancing age and immunosuppression, VZV reactivates to produce zoster (shingles). One of the most serious complications of zoster is VZV vasculopathy.

METHODS

We reviewed recent studies of stroke associated with varicella and zoster, how VZV vasculopathy is verified virologically, vaccination to prevent varicella and immunization to prevent zoster, and VZV in giant cell arteritis (GCA).

FINDINGS

We report recent epidemiological studies revealing an increased risk of stroke after zoster; the clinical, laboratory, and imaging features of VZV vasculopathy; that VZV vasculopathy is confirmed by the presence of either VZV DNA or anti-VZV IgG antibody in cerebrospinal fluid; special features of VZV vasculopathy in children; vaccination to prevent varicella and immunization to prevent zoster; and the latest evidence linking VZV to GCA.

CONCLUSION

In children and adults, VZV is a common cause of stroke.

Developments in Varicella Zoster Virus Vasculopathy

Varicella zoster virus (VZV) is a highly neurotropic human herpesvirus. Primary infection usually causes varicella (chicken pox), after which virus becomes latent in ganglionic neurons along the entire neuraxis. VZV reactivation results in zoster (shingles) which is frequently complicated by chronic pain (postherpetic neuralgia). VZV reactivation also causes meningoencephalitis, myelitis, ocular disorders, and vasculopathy, all of which can occur in the absence of rash. This review focuses on the association of VZV and stroke, and on the widening spectrum of disorders produced by VZV vasculopathy in immunocompetent and immunocompromised individuals, including recipients of varicella vaccine. Aside from ischemic stroke, VZV infection of cerebral arteries may lead to development of intracerebral aneurysms, with or without hemorrhage. Moreover, recent clinical-virological case reports and retrospective pathological-virological analyses of temporal arteries positive or negative for giant cell arteritis (GCA) indicate that extracranial VZV vasculopathy triggers the immunopathology of GCA. While many patients with GCA improve after corticosteroid treatment, prolonged corticosteroid use may potentiate VZV infection, leading to fatal vasculopathy in the brain and other organs.

Successful rescue of disseminated varicella infection with multiple organ failure in a pediatric living donor liver transplant recipient: a case report and literature review

A 12-year-old female patient with biliary atresia underwent living donor liver transplantation (LDLT). Twelve months after the LDLT, she developed acute hepatitis (alanine aminotransferase 584 IU/L) and was diagnosed with disseminated varicella-zoster virus (VZV) infection with high level of serum VZV-DNA (1.5 × 10⁵ copies/mL) and generalized vesicular rash. She had received the VZV vaccination when she was 5-years-old and had not been exposed to chicken pox before the LDLT, and her serum was positive for VZV immunoglobulin G at the time of the LDLT. Although she underwent treatment with intravenous acyclovir, intravenous immunoglobulin, and withdrawal of immunosuppressants, her symptoms worsened and were accompanied by disseminated intravascular coagulation, pneumonia, and encephalitis. These complications required treatment in the intensive care unit for 16 days. Five weeks later, her clinical findings improved, although her VZV-DNA levels remained high (8.5 × 10³copies/mL). Oral acyclovir was added for 2 weeks, and she was eventually discharged from our hospital on day 86 after admission; she has not experienced a recurrence. In conclusion, although disseminated VZV infection with multiple organ failure after pediatric LDLT is a life-threatening disease, it can be cured via an early diagnosis and intensive treatment.

Clinical and molecular aspects of the live attenuated Oka varicella vaccine

VZV is a ubiquitous member of the Herpesviridae family that causes varicella (chicken pox) and herpes zoster (shingles). Both manifestations can cause great morbidity and mortality and are therefore of significant economic burden. The introduction of varicella vaccination as part of childhood immunization programs has resulted in a remarkable decline in varicella incidence, and associated hospitalizations and deaths, particularly in the USA. The vaccine preparation, vOka, is a live attenuated virus produced by serial passage of a wild-type clinical isolate termed pOka in human and guinea pig cell lines. Although vOka is clinically attenuated, it can cause mild varicella, establish latency, and reactivate to cause herpes zoster. Sequence analysis has shown that vOka differs from pOka by at least 42 loci; however, not all genomes possess the novel vOka change at all positions, creating a heterogeneous population of genetically distinct haplotypes. This, together with the extreme cell-associated nature of VZV replication in cell culture and the lack of an animal model, in which the complete VZV life cycle can be replicated, has limited studies into the molecular basis for vOka attenuation. Comparative studies of vOka with pOka replication in T cells, dorsal root ganglia, and skin indicate that attenuation likely involves multiple mutations within ORF 62 and several other genes. This article presents an overview of the clinical aspects of the vaccine and current progress on understanding the molecular mechanisms that account for the clinical phenotype of reduced virulence.

Pathogenesis and current approaches to control of varicella-zoster virus infections

Varicella-zoster virus (VZV) was once thought to be a fairly innocuous pathogen. That view is no longer tenable. The morbidity and mortality due to the primary and secondary diseases that VZV causes, varicella and herpes zoster (HZ), are significant. Fortunately, modern advances, including an available vaccine to prevent varicella, a therapeutic vaccine to diminish the incidence and ameliorate sequelae of HZ, effective antiviral drugs, a better understanding of VZV pathogenesis, and advances in diagnostic virology have made it possible to control VZV in the United States. Occult forms of VZV-induced disease have been recognized, including zoster sine herpete and enteric zoster, which have expanded the field. Future progress should include development of more effective vaccines to prevent HZ and a more complete understanding of the consequences of VZV latency in the enteric nervous system.

Recombinant varicella-zoster virus vaccines as platforms for expression of foreign antigens

Varicella-zoster virus (VZV) vaccines induce immunity against childhood chickenpox and against shingles in older adults. The safety, efficacy, and widespread use of VZV vaccines suggest that they may also be effective as recombinant vaccines against other infectious diseases that affect the young and the elderly. The generation of recombinant VZV vaccines and their evaluation in animal models are reviewed. The potential advantages and limitations of recombinant VZV vaccines are addressed.

Review of the United States universal varicella vaccination program: Herpes zoster incidence rates, cost-effectiveness, and vaccine efficacy based primarily on the Antelope Valley Varicella Active Surveillance Project data

In a cooperative agreement starting January 1995, prior to the FDA's licensure of the varicella vaccine on March 17, the Centers for Disease Control and Prevention (CDC) funded the Los Angeles Department of Health Services' Antelope Valley Varicella Active Surveillance Project (AV-VASP). Since only varicella case reports were gathered, baseline incidence data for herpes zoster (HZ) or shingles was lacking. Varicella case reports decreased 72%, from 2834 in 1995 to 836 in 2000 at which time approximately 50% of children under 10 years of age had been vaccinated. Starting in 2000, HZ surveillance was added to the project. By 2002, notable increases in HZ incidence rates were reported among both children and adults with a prior history of natural varicella. However, CDC authorities still claimed that no increase in HZ had occurred in any US surveillance site. The basic assumptions inherent to the varicella cost-benefit analysis ignored the significance of exogenous boosting caused by those shedding wild-type VZV. Also ignored was the morbidity associated with even rare serious events following varicella vaccination as well as the morbidity from increasing cases of HZ among adults. Vaccine efficacy declined below 80% in 2001. By 2006, because 20% of vaccinees were experiencing breakthrough varicella and vaccine-induced protection was waning, the CDC recommended a booster dose for children and, in 2007, a shingles vaccination was approved for adults aged 60 years and older. In the prelicensure era, 95% of adults experienced natural chickenpox (usually as children)-these cases were usually benign and resulted in long-term immunity. Varicella vaccination is less effective than the natural immunity that existed in prevaccine communities. Universal varicella vaccination has not proven to be cost-effective as increased HZ morbidity has disproportionately offset cost savings associated with reductions in varicella disease. Universal varicella vaccination has failed to provide long-term protection from VZV disease.

The host immune response to varicella zoster virus

Varicella zoster virus (VZV) is a highly successful human pathogen, which is never completely eliminated from the host. VZV causes two clinically distinct diseases, varicella (chickenpox) during primary infection and herpes zoster (shingles) following virus reactivation from latency. Throughout its lifecycle the virus encounters the innate and adaptive immune response, and in order to prevent eradication it has developed many mechanisms to evade and overcome these responses. This review will provide a comprehensive overview of the host immune response to VZV infection, during the multiple stages of the virus lifecycle and at key sites of VZV infection. We will also briefly describe some of the strategies employed by the virus to overcome the host immune response and the ongoing challenges in further elucidating the interplay between VZV and the host immune response in an attempt to lead to better therapies and a ‘second generation’ vaccine for VZV disease.

Neurovirulence of varicella and the live attenuated varicella vaccine virus

Varicella-zoster virus (VZV) is a neurotropic herpesvirus, which can cause a variety of complications during varicella infections. These range from meningoencephalitis to polyneuritis to retinitis. After primary VZV infection, VZV enters the dorsal root ganglia in a latent state. Reactivation from latency leads to zoster. The velocity of VZV is 13 cm per day, as the virus travels from ganglion to skin. The live attenuated varicella vaccine virus is markedly less neurovirulent than the wild-type virus. Nevertheless, a few cases of herpes zoster due to the vaccine virus have been documented. Usually, herpes zoster occurs in the same arm as the vaccination, often 3 or more years after vaccination. Thus, herpes zoster in a vaccinee often represents a reactivation of vaccine virus that was carried to the cervical dorsal root ganglia from a site of local replication in the arm. Finally, the role of autophagy during VZV infection is discussed. Autophagosome formation is a prominent feature in the skin vesicles during both varicella and herpes zoster. Therefore, autophagy is one of the innate immune mechanisms associated with VZV infection in humans.

Novel genetic variation identified at fixed loci in ORF62 of the Oka varicella vaccine and in a case of vaccine-associated herpes zoster

The live attenuated Oka varicella vaccine (vOka), derived from clade 2 wild-type (wt) virus pOka, is used for routine childhood immunization in several countries, including the United States, which has caused dramatic declines in the incidence of varicella. vOka can cause varicella, establish latency, and reactivate to cause herpes zoster (HZ). Three loci in varicella-zoster virus (VZV) open reading frame 62 (ORF62) (106262, 107252, and 108111) are used to distinguish vOka from wt VZV. A fourth position (105705) is also fixed for the vOka allele in nearly all vaccine batches. These 4 positions and two vOka mutations (106710 and 107599) reportedly absent from Varivax were analyzed on Varivax-derived ORF62 TOPO TA clones. The wt allele was detected at positions 105705 and 107252 on 3% and 2% of clones, respectively, but was absent at positions 106262 and 108111. Position 106710 was fixed for the wt allele, whereas the vOka allele was present on 18.4% of clones at position 107599. We also evaluated the 4 vOka markers in an isolate obtained from a case of vaccine-caused HZ. The isolate carried the vOka allele at positions 105705, 106262, and 108111. However, at position 107252, the wt allele was present. Thus, all of the ORF62 vOka markers previously regarded as fixed occur as the wt allele in a small percentage of vOka strains. Characterization of all four vOka markers in ORF62 and of the clade 2 subtype marker in ORF38 is now necessary to confirm vOka adverse events.

Molecular studies of the Oka varicella vaccine

Varicella zoster virus (VZV) is one of eight members of the Herpesviridae family for which humans are the primary host; it causes two distinct diseases, varicella (chickenpox) and zoster (shingles). Varicella results from primary infection, during which the virus establishes latency in sensory neurons, a characteristic of all members of the Alphaherpesvirinae subfamily. Zoster is caused by reactivation of latent virus, which typically occurs when cellular immunity is impaired. VZV is the first human herpesvirus for which a vaccine has been licensed. The vaccine preparation, v-Oka, is a live-attenuated virus stock produced by the classic method of tissue culture passage in animal and human cell lines. Over 90 million doses of the vaccine have been administered in countries worldwide, including the USA, where varicella morbidity and mortality has declined dramatically. Over the last decade, several laboratories have been committed to investigating the mechanism by which the Oka vaccine is attenuated. Mutations have accumulated across the genome of the vaccine during the attenuation process; however, studies of the contribution of these changes to vaccine attenuation have been hampered by the lack of a suitable animal model of VZV disease and by the heterogeneity that exists among the viral population within the vaccine preparation. Notwithstanding, a wealth of data has been generated using various laboratory methodologies. Studies of the vaccine virus in human xenografts implanted in severe combined immunodeficiency-hu mice, have enabled analyses of the replication dynamics of the vaccine in dorsal root ganglia, T lymphocytes and skin. In vitro assays have been used to investigate the effect of vaccine mutations on viral gene expression and sequence analysis of vaccine rash viruses has permitted investigations into spread of the vaccine virus in a human host. We present here a review of what has been learned thus far about the molecular and phenotypic characteristics of the Oka vaccine.

Differentiated neuroblastoma cells provide a highly efficient model for studies of productive varicella-zoster virus infection of neuronal cells

Varicella-zoster virus (VZV) is a highly species-specific herpesvirus that targets sensory ganglionic neurons. This species specificity has limited the study of many aspects of VZV pathogenesis, including neuronal infection. We report development of a highly efficient neuroblastoma cell model to study productive VZV infection of neuronal cells. We show that differentiation of SH-SY5Y neuroblastoma cells yields a homogenous population of neuron-like cells that are permissive to the full VZV replicative cycle. These cells supported productive infection by both laboratory and clinical VZV isolates, including the live varicella vaccine. This model may enable rapid identification of genetic determinants facilitating VZV neurotropism.

Herpes zoster and meningitis due to reactivation of varicella vaccine virus in an immunocompetent child

Neurologic complications from varicella zoster virus (VZV) reactivation are rare. In this article, we describe a previously immunized child who developed herpes zoster with meningitis. Vaccine strain of VZV was recovered from a skin swab and the cerebrospinal fluid. Reactivation of the vaccine strain of VZV should be recognized as a potential cause of meningitis in children.

Varicella zoster disease of the central nervous system: epidemiological, clinical, and laboratory features 10 years after the introduction of the varicella vaccine

BACKGROUND

Since the introduction of live attenuated varicella zoster virus (VZV) vaccine in 1995 there has been a significant reduction in varicella incidence and its associated complications, but the impact on VZV-associated central nervous system (CNS) disease has not been assessed.

METHODS

In this descriptive study we evaluated patients referred to the California Encephalitis Project from 1998 to 2009 with VZV PCR-positive cerebrospinal fluid (CSF). Epidemiological, clinical, and laboratory data were collected using a standardized case form. Specimens were genotyped using multi-single nucleotide polymorphism (SNP) analysis.

RESULTS

Twenty-six specimens were genotyped from patients 12-85 years of age (median, 46 years). Clinical presentations included meningitis (50%), encephalitis (42%), and acute disseminated encephalomyelitis (ADEM) (8%). Only 11 patients (42%) had a concomitant herpes zoster rash. Genotype analysis identified 20 European Group (Clade1, Clade 3) strains; 4 Asian (Clade 2) strains, and 2 Mosaic Group (Clade 4, Clade VI) strains. One specimen was recognized as vaccine strain by identifying vaccine-associated SNPs.

CONCLUSIONS

VZV continues to be associated with CNS disease, with meningitis being the most frequent clinical presentation. CNS VZV disease often presented without accompanying zoster rash. Sequencing data revealed multiple genotypes, including 1 vaccine strain detected in the CSF of a young patient with meningitis.

Perspectives on vaccines against varicella-zoster virus infections

Primary infection with varicella-zoster virus (VZV) results in varicella which, in populations where immunization is not used, occurs mostly in children. Varicella is a generalized rash illness with systemic features such as fever and malaise. During varicella, VZV becomes latent in sensory ganglia of the individual, and in 70% it remains asymptomatic for their lifetime. The remaining 30% develop reactivation from latency, resulting in herpes zoster (HZ). HZ usually occurs in persons over the age of 50, and is manifested by a painful unilateral rash that usually lasts about 2 weeks and then may be followed by a chronic pain syndrome called post-herpetic neuralgia (PHN). VZV infections are notoriously more severe in immunocompromised hosts than in healthy individuals. Despite gaps in our understanding of the details of immunity to VZV, successful vaccines have been developed against both varicella and zoster.

Safety profile of live varicella virus vaccine (Oka/Merck): five-year results of the European Varicella Zoster Virus Identification Program (EU VZVIP)

BACKGROUND

VARIVAX (Oka/Merck) is a live varicella vaccine, licensed in Europe since 2003. In addition to routine safety surveillance, the Varicella Zoster Virus Identification Program (VZVIP) analyzes clinical samples to establish whether adverse events (AEs) are associated with wild-type (wt) or vaccine varicella zoster virus (vVZV) strain. The European VZVIP provides data on VZV clade distribution.

METHODS

Samples were collected from patients with selected AEs; the VZV strain was determined using polymerase chain reaction.

RESULTS

From October 2003 to September 2008, 1006 spontaneous AE reports were analyzed (88% non-serious). Samples from 76/585 cases with selected AEs were collected. Of 55 VZV-positive/typable samples, wtVZV was detected in 40 and vVZV in 15 samples. Most rashes (32/44) <or=42 days postvaccination were associated with wtVZV. For breakthrough varicella, 6/9 cases were wtVZV-positive; none were vVZV-positive. For herpes zoster 9/17 cases were VZV-positive: eight vVZV, one wtVZV. One case of mild encephalitis was associated with vVZV. One of three cases of suspected secondary vVZV transmission was confirmed. Most wtVZV was clade 3 and clade 1.

CONCLUSIONS

European experience confirms that Oka/Merck vaccine is generally well tolerated. wtVZV genotypes were consistent with the molecular epidemiology of VZV in Europe.

A spread-deficient cytomegalovirus for assessment of first-target cells in vaccination

Human cytomegalovirus (HCMV) is a human pathogen that causes severe disease primarily in the immunocompromised or immunologically immature individual. To date, no vaccine is available. We describe use of a spread-deficient murine CMV (MCMV) as a novel approach for betaherpesvirus vaccination. To generate a spread-deficient MCMV, the conserved, essential gene M94 was deleted. Immunization with MCMV-DeltaM94 is apathogenic and protective against wild-type challenge even in highly susceptible IFNalphabetaR(-/-) mice. MCMV-DeltaM94 was able to induce a robust CD4(+) and CD8(+) T-cell response as well as a neutralizing antibody response comparable to that induced by wild-type infection. Endothelial cells were identified as activators of CD8(+) T cells in vivo. Thus, the vaccination with a spread-deficient betaherpesvirus is a safe and protective strategy and allows the linkage between cell tropism and immunogenicity. Furthermore, genomes of MCMV-DeltaM94 were present in lungs 12 months after infection, revealing first-target cells as sites of genome maintenance.

Vaccine-associated herpes zoster ophthalmicus [correction of opthalmicus] and encephalitis in an immunocompetent child

Varicella-zoster virus vaccine has diminished the consequences of chicken pox in terms of health and economical burden. The increasing number of doses administered worldwide has revealed rare but important adverse effects that had not occurred during clinical trials. We report here the case of an immunocompetent 3(1/2)-year-old girl who developed encephalitis and herpes zoster opthalmicus 20 months after her immunization with varicella-zoster virus vaccine. Molecular analysis confirmed the vaccine strain as the causative agent. After an intravenous course with acyclovir, the child made a full recovery with no neurologic sequelae.

Incidence of herpes zoster among children vaccinated with varicella vaccine in a prepaid health care plan in the United States, 2002-2008

BACKGROUND

Herpes zoster (HZ), or shingles, is caused by reactivation of latent varicella-zoster virus after a primary infection with either wild-type or vaccine-type varicella-zoster virus, the latter having been introduced in 1995 for children. Since then, few population-based data about the incidence of childhood HZ are available.

METHODS

We identified children aged < or = 12 years who were vaccinated with 1 dose of varicella vaccine between 2002 and 2008 in a prepaid health plan and followed them through their electronic health records for a diagnosis of HZ. The medical records of these children were reviewed. Persistent and chronic conditions for these children before HZ were identified.

RESULTS

There were 172,163 children vaccinated, with overall follow-up of 446,027 person-years (Incidence rate = 27.4 per 100,000 person-years, 95% confidence interval: 22.7-32.7). Children vaccinated after age 5 years had a higher but not statistically significant different rate than children vaccinated between 12 and 18 months (34.3 vs. 28.5 per 100,000 person-years). Among children vaccinated between 12 and 18 months, incidence rates gradually increased each year in the first 4 years after vaccination (P < 0.001). Among the HZ cases, there were 1 (0.7%) case of lymphoid leukemia, 1 (0.7%) case of drug abuse, 16 (11.1%) cases of asthma with 3 or more acute exacerbations, 12 (8.3%) cases of developmental disorders, and 3 (2.1%) cases of psychological or mental disorders.

CONCLUSIONS

These data demonstrate that diagnosed HZ is rare among children following varicella vaccine. Despite the small numbers, the roles of delayed vaccination, severe asthma, and development disorders warrant further investigation. In the future, analyses of HZ isolates will be needed to identify the virus strains causing reactivation.