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

Effect of atopic conditions on development and recurrences of infectious keratitis

BACKGROUND

Atopic conditions are known to be associated with viral and bacterial infections. The purpose of this study was to determine the relationship between the effects of atopic conditions on the severity and recurrence of ocular infections including herpes simplex virus (HSV).

METHODS

This study was performed on 474 consecutive patients with infectious keratitis caused by bacteria, fungus, acanthamoeba, HSV, or varicella-zoster virus. The relationships between the atopic condition and specific infectious pathogens and HSV were determined using real-time PCR.

RESULTS

Our findings showed that atopic dermatitis (AD) was significantly associated with the incidence of HSV keratitis (odds ratio (OR), 10.2; P = 0.000). Other associations with AD were observed only with bacteria in an adverse manner. HSV proliferation in the lesions of patients with HSV keratitis whose AD was associated with non-infectious atopic blepharitis were significantly greater by 145-folds (P = 0.000). The presence of asthma or allergic rhinitis also increased the HSV DNA copy numbers. A recurrence of HSV keratitis was observed in 70 patients (43.2 %), and mean time to recurrence was 1647 days. Cox proportional hazard model indicated that the epithelial type of HSV recurrence but not the stromal type was associated with atopic conditions especially with AD. The factors significantly associated with a recurrence was AD associated with non-infectious atopic blepharitis (HR: 6.11, P = 0.000) and asthma (HR: 3.03, P = 0.025).

CONCLUSIONS

Atopic conditions, especially AD with atopic blepharitis, are significantly associated with the development, increased proliferation, and shorter time to a recurrence on HSV keratitis.

Effectiveness of the Recombinant Zoster Vaccine in Adults Aged 50 and Older in the United States: A Claims-Based Cohort Study

BACKGROUND

The recombinant zoster vaccine had over 90% efficacy in preventing herpes zoster in clinical trials. However, its effectiveness outside of a clinical trial setting has not been investigated. This study aimed to assess the effectiveness of the recombinant zoster vaccine in general practice.

METHODS

A de-identified administrative claims database, the OptumLabs Data Warehouse, was used to conduct this retrospective cohort study to assess the effectiveness of the recombinant zoster vaccine against herpes zoster in nonimmunocompromised, vaccine age-eligible individuals enrolled in the database for ≥365 days.

RESULTS

A total of 4 769 819 adults were included in this study, with 173 745 (3.6%) adults receiving 2 valid doses of the recombinant zoster vaccine. The incidence rate of herpes zoster was 258.8 (95% confidence interval [CI], 230.0-289.4) cases per 100 000 person-years in vaccinated persons compared with 893.1 (95% CI, 886.2-900.0) in unvaccinated persons. Recombinant zoster vaccine effectiveness was 85.5% (95% CI, 83.5-87.3%) overall, with an effectiveness of 86.8% (95% CI, 84.6-88.7%) in individuals 50 to 79 years old compared with 80.3% (95% CI, 75.1-84.3%) in individuals aged 80 and older. In patients with a history of live zoster vaccine within 5 years of study inclusion, vaccine effectiveness was 84.8% (95% CI, 75.3-90.7%).

CONCLUSIONS

Recombinant zoster vaccine effectiveness against herpes zoster was high in a real-world setting. Given the low vaccine coverage and high effectiveness, a major public health effort is needed to identify and address barriers to vaccination and increase immunization rates.

Insights on the Impact of External and Internal Boosting on Varicella-Zoster Virus Reactivation Based on Evidence From the First Decade of the United States Universal Varicella Vaccination Program

Since the licensure of the varicella vaccine in the United States in 1995 and the implementation of the universal varicella vaccination program, varicella infection rates, and associated morbidity and mortality rates have decreased. However, controversy exists over whether universal vaccination has resulted in an increased incidence of herpes zoster (HZ). In 1965, Dr. Hope-Simpson hypothesized that exogenous exposures to the wild-type varicella-zoster virus (wt-VZV) provide immune boosts that inhibit HZ; therefore, reducing the amount of circulating wt-VZV may have the negative effect of increasing the incidence of HZ. A historical review of data from the Centers for Disease Control and Prevention-sponsored Antelope Valley Varicella Active Surveillance Project, along with other studies, is provided to investigate the exogenous boosting hypothesis in the first decade post-vaccine licensure. These data indicated that adoption of universal varicella vaccination led to (1) significant HZ incidence rate increases among children, adolescents, and adults with a history of wild-type varicella and (2) decline in varicella vaccine efficacy after the initial post-licensure period. These effects were likely due to reduced exogenous exposures from children shedding wt-VZV. Appropriate methodologies for ongoing research are also discussed, both in studies during the first decade post-licensure and more recent work.

Effect of the varicella vaccination implementation on the development of herpes zoster in children and adolescents

Herpes zoster (HZ) is an infectious disease caused by latent varicella-zoster virus reactivation. There are conflicting reports on the varicella vaccine's effect on the incidence of HZ in children and adolescents. This study aimed to determine the impact of the single dose of varicella vaccination on HZ prevalence during childhood and adolescence. The study included children and adolescents aged <18 years who presented to the dermatology outpatient clinic between 2005 and 2019 and were diagnosed with HZ. Considering that the universal vaccination program started to be implemented in Turkey in 2013, non-vaccinated cases in the prevaccination period, vaccinated cases in the postvaccination period, and non-vaccinated patients in the postvaccination period were compared in terms of HZ prevalence and demographic features. After the initiation of the varicella vaccination program, the prevalence of HZ was found to decrease by 24.7% in all. The HZ prevalence was significantly reduced in vaccinated children, while the rate of decrease in non-vaccinated children was low (58.6% and 16.4%, respectively). The median age of the non-vaccinated cases in the postvaccination period (10 [min 0.5-max 17] years) was significantly higher compared to the other groups (p < 0.001). The number of cases aged <2 years was the highest in the vaccinated group (p < 0.001). Administration of a single dose of varicella vaccine was insufficient to decrease the prevalence of HZ <18 years of age. In the post-vaccination period, the frequency of HZ in unvaccinated cases increased in adolescence. In vaccinated children, HZ seems to develop at an earlier age.

What We Know Now: An Economic Evaluation of Chickenpox Vaccination and Dose Timing Using an Agent-Based Model

OBJECTIVES

The value of chickenpox vaccination is still debated in the literature and by jurisdictions worldwide. This uncertainty is reflected in the inconsistent uptake of the vaccine, where some countries offer routine childhood immunization programs, others have targeted programs, and in many the vaccine is only privately available. Even across the countries that have universal funding for the vaccine, there is a diversity of schedules and dosing intervals. Using an agent-based model of chickenpox and shingles, we conducted an economic evaluation of chickenpox vaccination in Alberta, Canada.

METHODS

We compared the cost-effectiveness of 2 common chickenpox vaccination schedules, specifically a long dosing interval (first dose: 12 months; second dose: 4-6 years) and a short dosing interval (first dose: 12 months; second dose: 18 months).

RESULTS

The economic evaluation demonstrated a shorter dosing interval may be marginally preferred, although it consistently led to higher costs from both the societal and healthcare perspectives. We found that chickenpox vaccination would be cost-saving and highly cost-effective from the societal and healthcare perspective, assuming there was no impact on shingles.

CONCLUSION

Chickenpox vaccine was cost-effective when not considering shingles and remained so even if there was a minor increase in shingles following vaccination. However, if chickenpox vaccination did lead to a substantial increase in shingles, then chickenpox vaccination was not cost-effective from the healthcare perspective.

Varicella vaccine dose depended effectiveness and waning among preschool children in Hong Kong

In Hong Kong, universal varicella vaccination was introduced in July 2014 with a two-dose schedule but the vaccines had been available in the private market since 1996. With data from varicella notification and surveys on immunization coverage, we used the screening method to estimate dose-specific varicella vaccine effectiveness (VE) among preschool children in Hong Kong before universal vaccination. We estimated the VE of one- and two-dose varicella vaccination against all notified varicella as 69.4% (95% confidence interval (95% CI) 69.5-71.2) and 93.4% (95% CI 91.7-94.7), respectively. We found that VE did not decrease with time since receipt. Varicella vaccine was more effective against complications (85.4% [95% CI 48.8-95.8] for one dose and 100% [95% CI -Inf to 100] for two doses) and against hospital admission (75.2% [95% CI 53.4-86.8] for one dose and 93.1% [95% CI 47.1-99.1] for two doses). Lower protection of one-dose varicella vaccine resulted in breakthrough varicella. Under universal vaccination, second-dose varicella vaccine (given as combined measles, mumps, rubella and varicella vaccine) was first scheduled for children when they reach primary one (about 6 years of age) and was recently advanced to 18 months of age. Shortening the interval between the first dose and second dose of varicella vaccination should reduce breakthrough varicella and outbreaks in preschool.

Pediatric Herpes Zoster

A 10-year-old male vaccinated against varicella had developed left-sided rashes on his thoracic region in single dermatomal distribution, which is consistent with herpes zoster. Although herpes zoster is uncommon in children, especially with the current vaccination regimen, this case report serves as a reminder to consider it in one’s differential diagnoses, even in the immunocompetent, fully immunized pediatric patient. This is a case report of a previously healthy, fully vaccinated child who developed herpes zoster.

Do varicella vaccination programs change the epidemiology of herpes zoster? A comprehensive review, with focus on the United States

Introduction: Policy-makers in many countries have been wary of introducing varicella vaccination programs because of concerns that reduced exposures to varicella-zoster virus could increase herpes zoster (HZ) incidence. The U.S. introduced varicella vaccination in 1996 and has empiric evidence regarding this concern. Areas covered: This comprehensive review provides background emphasizing the epidemiology of varicella and of HZ in the U.S. before and after the introduction of their respective vaccines. The epidemiology is complex, and interpretation is complicated by methodologic challenges, by unexplained increases in age-specific HZ incidence that preceded varicella vaccination, and by introduction of vaccines for prevention of HZ. Nonetheless, observations from studies using different platforms and designs have yielded consistent findings, suggesting they are robust. Expert opinion: There has been no evidence that the U.S. varicella vaccination program increased HZ incidence in the general adult population over baseline trends. Furthermore, HZ incidence in children is declining. The U.S. experience can inform the development of new generations of models to predict HZ trends. More importantly, it provides reassurance for countries considering varicella vaccination that an effective program can reduce varicella morbidity and mortality while reducing the likelihood of HZ among children, and potentially, over time, across the entire population.

A clinico-epidemiological multicenter study of herpes zoster in immunocompetent and immunocompromised hospitalized children

Purpose

There are limited population-based data regarding herpes zoster in children. Thus we conducted a multi-institutional epidemiological analysis of herpes zoster in children and comparative analysis according to their immune status.

Materials and Methods

The study included 126 children under the age of 18 years who were hospitalized for herpes zoster at 8 hospitals in South Korea, between July 2009 and June 2015. The subjects were divided into 2 groups according to their immune status, and medical records were reviewed.

Results

There were 61 cases (48.4%) in the immunocompetent group and 65 cases (51.6%) in the immunocompromised group. Median age was older in immunocompromised group (11.4 vs. 8.6) (p<0.001). The mean duration of hospitalization was longer in immunocompromised group (11.0 vs. 6.6) (p<0.001). Patients were treated with oral or intravenous antiviral agents. A total of 12 in immunocompetent group were cured only by oral acyclovir. No treatment failure was found in both groups. Six immunocompromised patients had postherpetic neuralgia and 1 case was in immunocompetent group. In immunocompetent children, herpes zoster was likely caused by early varicella infection. There was no increase in progression of severity in both groups due to appropriate treatment.

Conclusion

Early initiation of therapy is necessary for those in immunocompromised conditions. And inactivated herpes zoster vaccination may be considered in immunocompromised adolescents in the future.

Incidence of Herpes Zoster Among Children: 2003-2014

BACKGROUND AND OBJECTIVES

After the 1996 introduction of routine varicella vaccination in the United States, most studies evaluating pediatric herpes zoster (HZ) incidence reported lower incidence over time, with varying degrees of decline. Using the combined databases of 6 integrated health care organizations, we examined HZ incidence in children over a 12-year period in the varicella vaccine era.

METHODS

This study included children aged 0 through 17 years from 2003 through 2014. Using electronic medical records, we identified HZ cases through International Classification of Diseases, Ninth Revision diagnosis code 053. We calculated HZ incidence rates per 100 000 person years of health plan membership for all children and among children who were vaccinated versus unvaccinated. We calculated rates for the 12-year period and examined temporal trends. Among children who were vaccinated, we compared HZ rates by month and year of age at vaccination.

RESULTS

The study included 6 372 067 children with ≥1 month of health plan membership. For the 12-year period, the crude HZ incidence rate for all subjects was 74 per 100 000 person years, and the rate among children who were vaccinated was 38 per 100 000 person years, which was 78% lower than that among children who were unvaccinated (170 per 100 000 person years; P < .0001). Overall HZ incidence declined by 72% (P < .0001) from 2003 through 2014. Annual rates in children who were vaccinated were consistently lower than in children who were unvaccinated.

CONCLUSIONS

With this population-based study, we confirm the decline in pediatric HZ incidence and the significantly lower incidence among children who are vaccinated, reinforcing the benefit of routine varicella vaccination to prevent pediatric HZ.

Vaccine-induced antibodies target sequestered viral antigens to prevent ocular HSV-1 pathogenesis, preserve vision, and preempt productive neuronal infection

The cornea is essential for vision yet highly sensitive to immune-mediated damage following infection. Generating vaccines that provide sterile immunity against ocular surface pathogens without evoking vision loss is therefore clinically challenging. Here, we tested a prophylactic live-attenuated vaccine against herpes simplex virus type 1 (HSV-1), a widespread human pathogen that can cause corneal blindness. Parenteral vaccination of mice resulted in sterile immunity to subsequent HSV-1 challenge in the cornea and suppressed productive infection of the nervous system. This protection was unmatched by a relevant glycoprotein subunit vaccine. Efficacy of the live-attenuated vaccine involved a T-dependent humoral immune response and complement C3 but not Fcγ-receptor 3 or interferon-α/β signaling. Proteomic analysis of viral proteins recognized by antiserum revealed an unexpected repertoire dominated by sequestered antigens rather than surface-exposed envelope glycoproteins. Ocular HSV-1 challenge in naive and subunit-vaccinated mice triggered vision loss and severe ocular pathologies including corneal opacification, scar formation, neovascularization, and sensation loss. However, corneal pathology was absent in mice receiving the live-attenuated vaccine concomitant with complete preservation of visual acuity. Collectively, this is the first comprehensive report of a prophylactic vaccine candidate that elicits resistance to ocular HSV-1 infection while fully preserving the cornea and visual acuity.

Implementing Universal Varicella Vaccination in Europe: The Path Forward

Varicella is a common vaccine-preventable disease that usually presents as a mild disorder but can lead to severe complications. Before the implementation of universal varicella vaccination (UVV) in some European countries, the burden of varicella disease was broadly similar across the region. Despite this, countries adopted heterogeneous varicella vaccination strategies. UVV is currently recommended in 12 European countries. Known barriers to UVV implementation in Europe include (1) a perceived low disease burden and low public health priority; (2) cost-effectiveness and funding availability; (3) concerns related to a shift in varicella disease and incidence of herpes zoster and (4) safety concerns related to measles, mumps, rubella and varicella-associated febrile seizures after the first dose. Countries that implemented UVV experienced decreases in varicella incidence, hospitalizations and complications, showing overall beneficial impact. Alternative strategies targeting susceptible individuals at higher risk of complications have been less effective. This article discusses ways to overcome the barriers to move varicella forward as a truly vaccine preventable disease.

Global impact of varicella vaccination programs

Although varicella is usually a mild and self-limited disease, complications can occur. In 1998, the World Health Organization recommended varicella vaccination for countries where the disease has a significant public health burden. Nonetheless, concerns about a shift in the disease to older groups, an increase in herpes zoster in the elderly and cost-effectiveness led many countries to postpone universal varicella vaccine introduction. In this review, we summarize the accumulating evidence, available mostly from high and middle-income countries supporting a high impact of universal vaccination in reductions of the incidence of the disease and hospitalizations and its cost-effectiveness. We have also observed the effect of herd immunity and noted that there is no definitive and consistent association between vaccination and the increase in herpes zoster incidence in the elderly.

Herpes zoster at the vaccination site in immunized healthy children

In this case series, we report seven immunized healthy children without underlying immunodeficiency who presented with herpes zoster that correlated with varicella-zoster vaccination site. The morphology of the lesions included erythematous papules, pseudovesicles, and plaques, with associated pain in two and pruritus in three patients; systemic symptoms ranged from none to low-grade fevers, upper respiratory symptoms, and joint pain. These cases highlight the clinical, diagnostic, and therapeutic implications of herpes zoster in vaccinated children.

Early impact of universal varicella vaccination on childhood varicella and herpes zoster hospitalizations in Brazil

INTRODUCTION

The Brazilian childhood National Immunization Program (NIP) introduced live and attenuated varicella vaccination in a single dose, combined as tetraviral vaccine, at 15 months of age in the whole country, during September to December of 2013. The aim of this study was to report trends in incidence of childhood hospital admissions related to varicella and zoster in Brazil from 2003 to 2016, including the first three years after vaccine introduction.

METHODS

The number and incidence of hospital admission in patients aged less than 20 years in Brazilian public health system with an admission diagnosis of varicella and zoster from 2003 to 2016 were analyzed and pre (2003-2013) and post-vaccination periods (2014-2016) were compared. The data were obtained from DATASUS, a Brazilian government's open-access public health database system, and analyzed adjusting for secular trend and seasonality if a statistically significant change was found.

RESULTS

During the study period, 69,791 admissions due to varicella and herpes zoster occurred in the children younger than 20 years. After adjusting for seasonality, the incidence of hospitalizations decreased from 27.33 to 14.33 per 100000 per year, which corresponds to a reduction of 47.6% (95% confidence interval 18.19-77.04%, p < 0.001) in the vaccinated age group (1-4 years) in 2014-2016 compared to pre-vaccination period. The changes were not significant in the unvaccinated age groups.

CONCLUSION

The hospitalizations due to varicella and herpes zoster were decreased by half early after the introduction of a single dose of tetraviral vaccine in NIP in the vaccinated children. Further studies may assess duration and intensity of this effect, as well as the indirect effect in the unvaccinated age groups.

Pediatric vaccine-strain herpes zoster: a case series

BACKGROUND/OBJECTIVES

Herpes zoster (HZ) is caused by reactivation of the varicella zoster virus (VZV), and typically causes a painful, vesicular, dermatomal rash in adults over the age of fifty. However, HZ has been known to present in immunocompetent pediatric patients, which account for under 1% of total cases. Pediatric cases are typically caused by natural infection with VZV, but among vaccinated children up to half of cases can be due to vaccine-strain VZV. We present two such cases of vaccine-strain HZ in pediatric patients.

METHODS

This is a retrospective study of two cases seen at UCLA-affiliated sites. PCR and Sanger sequencing, using previously described PCR primers, determined the presence of two vaccine-strain-specific single nucleotide polymorphisms.

RESULTS

We report two cases of vaccine-strain HZ in immunocompetent pediatric patients who had previously received the varicella vaccine, affecting the right thigh in the first patient and the left leg in the second. Varicella-strain VZV positivity was confirmed by PCR. Both patients had received the varicella vaccine at 12 months of age. Both patients achieved complete resolution of symptoms after 7-day courses of acyclovir.

CONCLUSIONS

While vaccination against VZV has overall reduced the incidence of both varicella and HZ in US children, given the widespread use of the VZV vaccine, awareness of the possibility of vaccine-induced HZ remains an important consideration.

Update on Incidence of Herpes Zoster Among Children and Adolescents After Implementation of Varicella Vaccination, Antelope Valley, CA, 2000 to 2010

BACKGROUND

Changes in herpes zoster (HZ) epidemiology are expected with childhood varicella vaccination. We reported previously that during 2000 to 2006 HZ incidence decreased 55% in children <10 years of age, while among 10- to 19-year olds it increased by 63%. We update the analysis with 4 additional years of data.

METHODS

Population-based active surveillance was conducted for HZ in Antelope Valley, California. Structured telephone interviews and medical chart reviews collected data on demographics, varicella vaccinations, disease histories and clinical information. We calculated HZ incidence for 2007 to 2010 and assessed trends since 2000.

RESULTS

Among children <10 years of age, HZ incidence continued the decreasing trend previously reported. During 2007 to 2010, the average incidence was 12.8 cases/100,000 children compared with 41.6 cases/100,000 children during 2000 to 2006, a 69% decline (P < 0.0001). For the 10- to 19-year olds, during 2007 to 2010 HZ incidence did not continue the increasing trend reported from 2000 to 2006; lower rates than in 2006 were observed in 3 of the 4 additional years evaluated. During 2007 to 2010 the average incidence was 78.2 cases/100,000 children compared with 68.0 cases/100,000 children during 2000 to 2006, a 13% increase (P = 0.123), with substantial fluctuation in annual rates throughout the 11 years of surveillance.

CONCLUSIONS

During the mature varicella vaccination program, declines in HZ incidence among children <10 years of age continued through 2010. Among the 10- to 19-year olds, the increase reported through 2006 did not continue further and lower rates than in 2006 were observed through 2010. Widespread use of varicella vaccine could reduce HZ incidence among vaccinated populations. Ongoing monitoring of HZ incidence is needed to detect and understand changes in HZ epidemiology in the varicella vaccine era.

Increasing Incidence of Herpes Zoster Over a 60-year Period From a Population-based Study

BACKGROUND

Temporal increases in the incidence of herpes zoster (HZ) have been reported but studies have examined short study periods, and the cause of the increase remains unknown. We examined the long-term trend of HZ.

METHODS

A population-based cohort study was conducted in Olmsted County, Minnesota, using data from 1945-1960 and 1980-2007. Medical records review of possible cases was performed to confirm incident cases of HZ, the patient's immune status, and prescribing of antivirals for HZ. We examined the relative change in the temporal trend in the incidence rates before and after the introduction of the varicella vaccination program.

RESULTS

Of the 8017 patients with HZ, 58.7% were females and 6.6% were immunocompromised. The age- and sex-adjusted incidence rate of HZ increased from 0.76 per 1000 person-years (PY) (95% confidence interval [CI], .63-.89) in 1945-1949 to 3.15 per 1000 PY (95% CI, 3.04-3.26) in 2000-2007. The rate of increase across the time period was 2.5% per year after adjusting for age and sex (adjusted incidence rate ratio, 1.025 [95% CI, 1.023-1.026]; P < .001). The incidence of HZ significantly increased among all age groups and both sexes. We found no change in the rate of increase before vs after the introduction of the varicella vaccination program.

CONCLUSIONS

The incidence of HZ has increased >4-fold over the last 6 decades. This increase is unlikely to be due to the introduction of varicella vaccination, antiviral therapy, or change in the prevalence of immunocompromised individuals.

In vitro system using human neurons demonstrates that varicella-zoster vaccine virus is impaired for reactivation, but not latency

Varicella-zoster virus (VZV) establishes latency in human sensory and cranial nerve ganglia during primary infection (varicella), and the virus can reactivate and cause zoster after primary infection. The mechanism of how the virus establishes and maintains latency and how it reactivates is poorly understood, largely due to the lack of robust models. We found that axonal infection of neurons derived from hESCs in a microfluidic device with cell-free parental Oka (POka) VZV resulted in latent infection with inability to detect several viral mRNAs by reverse transcriptase-quantitative PCR, no production of infectious virus, and maintenance of the viral DNA genome in endless configuration, consistent with an episome configuration. With deep sequencing, however, multiple viral mRNAs were detected. Treatment of the latently infected neurons with Ab to NGF resulted in production of infectious virus in about 25% of the latently infected cultures. Axonal infection of neurons with vaccine Oka (VOka) VZV resulted in a latent infection similar to infection with POka; however, in contrast to POka, VOka-infected neurons were markedly impaired for reactivation after treatment with Ab to NGF. In addition, viral transcription was markedly reduced in neurons latently infected with VOka compared with POka. Our in vitro system recapitulates both VZV latency and reactivation in vivo and may be used to study viral vaccines for their ability to establish latency and reactivate.

Epidemiology of pediatric herpes zoster after varicella infection: a population-based study

BACKGROUND

There are limited population-based data regarding pediatric herpes zoster (HZ).

METHODS

Children aged <12 years with varicella infections between 2000 and 2006 were identified from a national population-based database and followed-up for a diagnosis of HZ until December 2008. Since a routine varicella vaccination program was started in 2004, vaccinated children without medically attended varicella were identified between 2004 and 2006, and followed-up for a diagnosis of HZ until December 2008.

RESULTS

Of 27 517 children with medically attended varicella, 428 developed HZ. The incidence of HZ was 262.1 per 100 000 person-years. Of 25 132 vaccinated children without medically attended varicella, 106 developed HZ. The incidence of HZ was 93.3 per 100 000 person-years. The mean duration from varicella to HZ was 4.12 years. Children diagnosed with varicella at aged <2 years had a higher incidence (P < .001) and shorter duration (P = .04) than those diagnosed aged ≧2 years. Children diagnosed with varicella aged ≥2 but <8 years had a significantly increased incidence of HZ after than before the vaccination program (relative risk = 1.85 at 3 years of follow-up, P = .03). Children with varicella infections had a significantly greater risk of HZ than vaccinated children without a history of varicella (relative risk = 2.31 at 4 years of follow-up, P < .001).

CONCLUSIONS

This study demonstrates the population-based epidemiologic characteristics of pediatric HZ among those who contracted varicella. In the early postvaricella vaccination period, an increased HZ incidence was observed among children with varicella infection aged ≥2 years.

Risks for infection in patients with asthma (or other atopic conditions): is asthma more than a chronic airway disease?

Most of the research effort regarding asthma has been devoted to its causes, therapy, and prognosis. There is also evidence that the presence of asthma can influence patients' susceptibility to infections, yet research in this aspect of asthma has been limited. There is additional debate in this field, with current literature tending to view the increased risk of infection among atopic patients as caused by opportunistic infections secondary to airway inflammation, especially in patients with severe atopic diseases. However, other evidence suggests that such risk and its underlying immune dysfunction might be a phenotypic or clinical feature of atopic conditions. This review argues (1) that improved understanding of the effects of asthma or other atopic conditions on the risk of microbial infections will bring important and new perspectives to clinical practice, research, and public health concerning atopic conditions and (2) that research efforts into the causes and effects of asthma must be juxtaposed because they are likely to guide each other.

Successes and challenges in varicella vaccine

Varicella is a highly contagious disease caused by primary infection with varicella zoster virus (VZV). VZV infection, as well as varicella vaccination, induces VZV-specific antibody and T-cell-mediated immunity, essential for recovery. The immune responses developed contribute to protection following re-exposure to VZV. When cell-mediated immunity declines, as occurs with aging or immunosuppression, reactivation of VZV leads to herpes zoster (HZ). It has been almost 20 years since universal varicella vaccination has been implemented in many areas around the globe and this has resulted in a significant reduction of varicella-associated disease burden. Successes are reviewed here, whilst emphasis is put on the challenges ahead. Most countries that have not implemented routine childhood varicella vaccination have chosen to vaccinate high-risk groups alone. The main reasons for not introducing universal vaccination are discussed, including fear of age shift of peak incidence age and of HZ incidence increase. Possible reasons for not observing the predicted increase in HZ incidence are explored. The advantages and disadvantages of universal vs targeted vaccination as well as different vaccination schedules are discussed.

Vaccination to prevent varicella: Goldman and King's response to Myers' interpretation of Varicella Active Surveillance Project data

BACKGROUND

There is increasing evidence that herpes zoster (HZ) incidence rates among children and adults (aged <60 years) with a history of natural varicella are influenced primarily by the frequency of exogenous exposures, while asymptomatic endogenous reactivations help to cap the rate at approximately 550 cases/100,000 person-years when exogenous boosting becomes rare. The Antelope Valley Varicella Active Surveillance Project was funded by the Centers for Disease Control and Prevention in 1995 to monitor the effects of varicella vaccination in one of the three representative regions of the United States. The stability in the data collection and number of reporting sites under varicella surveillance from 1995-2002 and HZ surveillance during 2000-2001 and 2006-2007 contributed to the robustness of the discerned trends.

DISCUSSION

Varicella vaccination may be useful for leukemic children; however, the target population in the United States is all children. Since the varicella vaccine inoculates its recipients with live, attenuated varicella-zoster virus (VZV), clinical varicella cases have dramatically declined. Declining exogenous exposures (boosts) from children shedding natural VZV have caused waning cell-mediated immunity. Thus, the protection provided by varicella vaccination is neither lifelong nor complete. Moreover, dramatic increases in the incidence of adult shingles cases have been observed since HZ was added to the surveillance in 2000. In 2013, this topic is still debated and remains controversial in the United States.

SUMMARY

When the costs of the booster dose for varicella and the increased shingles recurrences are included, the universal varicella vaccination program is neither effective nor cost-effective.

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.

35th Annual Pediatric Infectious Diseases Society Awards

The following is a compilation of the 2013 Pediatric Infectious Diseases Society Awards presented on Monday, May 6, 2013 during the Pediatric Academic Societies meeting in Washington, DC. Award summaries were adapted from submissions provided by the nominating physician.

Increased risk of herpes zoster in children with asthma: a population-based case-control study

OBJECTIVE

To determine the risk of herpes zoster (HZ) in children with and without asthma.

STUDY DESIGN

This study was designed as a population-based case-control study. We examined all children (aged <18 years) with possible HZ in Olmsted County, Minnesota, between 1996 and 2001 (n = 306; identified by International Classification of Diseases, Eighth Revision codes and predetermined criteria for HZ) to identify true cases. To determine the association between asthma and HZ, we compared the frequency of asthma among children with HZ with that among age- and sex-matched corresponding controls (1:1 matching) who resided in Olmsted County, Minnesota, during the study period. Asthma was ascertained based on predetermined criteria. A conditional logistic regression model was used to calculate ORs and 95% CIs.

RESULTS

We identified 277 eligible patients with HZ, 63 (23%) of whom had a history of asthma before the index date of HZ, compared with 35 of 277 (12.6%) matched controls (aOR, 2.09; 95% CI, 1.24-3.52; P = .006), adjusting for varicella vaccination and atopy status. The population-attributable risk percentage was 12%. Controlling for asthma and atopy status, varicella vaccination was associated with reduced risk of HZ (aOR, 0.44; 95% CI, 0.21-0.92; P = .028).

CONCLUSION

Asthma may be an unrecognized risk factor for reactivation of a non-airway-related latent infection such as HZ in children.

Herpesviruses and the microbiome

The focus of this article will be to examine the role of common herpesviruses as a component of the microbiome of atopic patients and to review clinical observations suggesting that atopic patients might be predisposed to more severe and atypical herpes-related illness because their immune response is biased toward a TH2 cytokine profile. Human populations are infected with 8 herpesviruses, including herpes simplex virus HSV1 and HSV2 (also termed HHV1 and HHV2), varicella zoster virus (VZV or HHV3), EBV (HHV4), cytomegalovirus (HHV5), HHV6, HHV7, and Kaposi sarcoma-associated herpesvirus (termed KSV or HHV8). Herpesviruses are highly adapted to lifelong infection of their human hosts and thus can be considered a component of the human "microbiome" in addition to their role in illness triggered by primary infection. HSV1 and HSV2 infection and reactivation can present with more severe cutaneous symptoms termed eczema herpeticum in the atopic population, similar to the more severe eczema vaccinatum, and drug reaction with eosinophilia and systemic symptoms syndrome (DRESS) is associated with reactivation of HSV6 and possibly other herpesviruses in both atopic and nonatopic patients. In this review evidence is reviewed that primary infection with herpesviruses may have an atypical presentation in the atopic patient and conversely that childhood infection might alter the atopic phenotype. Reactivation of latent herpesviruses can directly alter host cytokine profiles through viral expression of cytokine-like proteins, such as IL-10 (EBV) or IL-6 (cytomegalovirus and HHV8), viral encoded and secreted siRNA and microRNAs, and modulation of expression of host transcription pathways, such as nuclear factor κB. Physicians caring for allergic and atopic populations should be aware of common and uncommon presentations of herpes-related disease in atopic patients to provide accurate diagnosis and avoid unnecessary laboratory testing or incorrect diagnosis of other conditions, such as drug allergy or autoimmune disease. Antiviral therapy and vaccines should be administered promptly when indicated clinically.

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.

Varicella zoster vaccines and their implications for development of HSV vaccines

Live attenuated vaccines to prevent varicella and zoster have been available in the US for the past 17 years, with a resultant dramatic decrease in varicella incidence and a predicted future decrease in the incidence of zoster. The pathogenesis and immune responses to varicella zoster virus (VZV) as well as the safety and effectiveness of VZV vaccines are reviewed. The lack of sterilizing immunity provided by VZV vaccines has not prevented them from being safe and effective. Virological and pathological information concerning parallels and differences between VZV and herpes simplex virus (HSV) are highlighted. Although VZV and HSV are distinct pathogens, they appear to have similarities in target organs and immunity that provide an expectation of a high likelihood for the success of vaccination against HSV, and predicted to be similar to that of VZV.

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.

Herpes zoster incidence among insured persons in the United States, 1993-2006: evaluation of impact of varicella vaccination

BACKGROUND

herpes zoster (HZ) is caused by reactivation of latent varicella zoster virus and is often associated with substantial pain and disability. Baseline incidence of HZ prior to introduction of HZ vaccine is not well described, and it is unclear whether introduction of the varicella vaccination program in 1995 has altered the epidemiology of HZ. We examined trends in the incidence of HZ and impact of varicella vaccination on HZ trends using a large medical claims database.

METHODS

medical claims data from the MarketScan databases were obtained for 1993-2006. We calculated HZ incidence using all persons with a first outpatient service associated with a 053.xx code (HZ ICD-9 code) as the numerator, and total MarketScan enrollment as the denominator; HZ incidence was stratified by age and sex. We used statewide varicella vaccination coverage in children aged 19-35 months to explore the impact of varicella vaccination on HZ incidence.

RESULTS

HZ incidence increased for the entire study period and for all age groups, with greater rates of increase 1993-1996 (P < .001). HZ rates were higher for females than males throughout the study period (P < .001) and for all age groups (P < .001). HZ incidence did not vary by state varicella vaccination coverage.

CONCLUSIONS

HZ incidence has been increasing from 1993-2006. We found no evidence to attribute the increase to the varicella vaccine program.

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.

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.