Estimation of the burden of varicella in Europe before the introduction of universal childhood immunization

Infection and Pediatric Arterial Ischemic Stroke Presumably Related to Focal Cerebral Arteriopathy: Data From the COVID-19 Pandemic

BACKGROUND

Infection may trigger pediatric arterial ischemic stroke (PAIS), notably when related to focal cerebral arteriopathy. Community- and individual-level nonpharmaceutical interventions during the COVID-19 pandemic resulted in a major decrease in pediatric viral infections. We explored the consequences on the incidence of PAIS.

METHODS

Using national public health databases, we identified children hospitalized between 2015 and 2022 with PAIS. Using an age proxy (29 days to 7 years) and excluding patients with cardiac and hematologic conditions, we focused on children with PAIS presumably related to focal cerebral arteriopathy or with no definite cause. Considering the delay between infection and PAIS occurrence, we compared a prepandemic reference period, a period with nonpharmaceutical interventions, and a post-nonpharmaceutical intervention period.

RESULTS

Interrupted time-series analyses of the monthly incidence of PAIS in this group showed a significant decrease in the nonpharmaceutical intervention period compared with the prepandemic period: -33.5% (95% CI, -55.2%, -1.3%); P=0.043.

CONCLUSIONS

These data support the association between infection and PAIS presumably related to focal cerebral arteriopathy.

The clinical and economic costs associated with regional disparities in varicella vaccine coverage in Italy over 50 years (2020-2070)

Italy implemented two-dose universal varicella vaccination (UVV) regionally from 2003 to 2013 and nationally from 2017 onwards. Our objective was to analyze regional disparities in varicella outcomes resulting from disparities in vaccine coverage rates (VCRs) projected over a 50-year time-horizon (2020-2070). A previously published dynamic transmission model was updated to quantify the potential public health impact of the UVV program in Italy at the national and regional levels. Four 2-dose vaccine strategies utilizing monovalent (V) and quadrivalent (MMRV) vaccines were evaluated for each region: (A) MMRV-MSD/MMRV-MSD, (B) MMRV-GSK/MMRV-GSK, (C) V-MSD/MMRV-MSD, and (D) V-GSK/MMRV-GSK. Costs were reported in 2022 Euros. Costs and quality-adjusted life-years (QALYs) were discounted 3% annually. Under strategy A, the three regions with the lowest first-dose VCR reported increased varicella cases (+ 34.3%), hospitalizations (+ 20.0%), QALYs lost (+ 5.9%), payer costs (+ 22.2%), and societal costs (+ 14.6%) over the 50-year time-horizon compared to the three regions with highest first-dose VCR. Regions with low first-dose VCR were more sensitive to changes in VCR than high first-dose VCR regions. Results with respect to second-dose VCR were qualitatively similar, although smaller in magnitude. Results were similar across all vaccine strategies.

Varicella mimicking complications of acute rhinosinusitis in an infant

Varicella is the manifestation of primary infection with the varicella-zoster virus, mainly affecting preschool and school-aged children. The children suffer from a generalised, vesicular rash and fever. Despite the infection's typically non-threatening course, a variety of severe complications have been described.The authors present the case of a female infant suffering from varicella and developing preseptal cellulitis with a frontal abscess while being treated with intravenous antibiotics. Otorhinolaryngology consultation was sought since the clinical image was highly suggestive for sinusitis complications, namely orbital cellulitis and frontal bone osteomyelitis (Pott's puffy tumour). However, the child was below the age of frontal sinus development and there was no other apparent sign of sinonasal involvement. Ultrasonography revealed a mid-frontal collection without signs of abscess formation preseptally or postseptally, leading to the diagnosis of cutaneous superinfection of varicella lesions. The frontal abscess was drained, and the child fully recovered under antibiotic treatment.

Clinical and Economic Burden of Antibiotic Use Among Pediatric Patients With Varicella Infection in the Outpatient Setting: A Retrospective Cohort Analysis of Real-world Data in France

BACKGROUND

Varicella infects 90% of children before age 9. Though varicella is self-limiting, its complications may require antibiotics, though how antibiotics are utilized for varicella in France is not well known. This study assessed antibiotic use and costs associated with varicella and its complications in pediatric patients managed in the outpatient setting in France.

METHODS

A retrospective cohort study using the Cegedim Strategic Data-Longitudinal Patient Database, an electronic medical record database from general practitioners and office-based specialists in France, was conducted. Children <18 years old diagnosed with varicella between January 2014 and December 2018 with 3-month follow-up available were included. We used descriptive analysis to assess varicella-related complications, medication use, healthcare resource utilization and costs.

RESULTS

Overall, 48,027 patients were diagnosed with varicella; 15.3% (n = 7369) had ≥1 varicella-related complication. Antibiotics were prescribed in up to 25.1% (n = 12,045/48,027) of cases with greater use in patients with complications (68.1%, n = 5018/7369) compared with those without (17.3%, n = 7027/40,658). Mean medication and outpatient varicella-related costs were €32.82 per patient with medications costing a mean of €5.84 per patient; antibiotics contributed ~23% to total costs annually.

CONCLUSION

This study showed high antibiotic use for the management of varicella and its complications. A universal varicella vaccination program could be considered to alleviate complications and associated costs in France.

Chickenpox Outbreaks in Three Refugee Camps on Mainland Greece, 2016-2017: A Retrospective Study

INTRODUCTION

Displaced populations face disproportionately high risk of communicable disease outbreaks given the strains of travel, health care circumstances in their country of origin, and limited access to health care in receiving countries.

STUDY OBJECTIVE

Understanding the role of demographic characteristics in outbreaks is important for timely and efficient control measures. Accordingly, this study assesses chickenpox outbreaks in three large refugee camps on mainland Greece from 2016 - 2017, using clinical line-list data from Médecins du Monde (MdM) clinics.

METHODS

Clinical line-list data from MdM clinics operating in Elliniko, Malakasa, and Raidestos camps in mainland Greece were used to characterize chickenpox outbreaks in these camps. Logistic regression was used to compare the odds of chickenpox by sex, camp, and yearly increase in age. Incidences were calculated for age categories and for sex for each camp outbreak.

RESULTS

Across camps, the median age was 19 years (IQR: 7.00 - 30.00 years) for all individuals and five years (IQR: 2.00 - 8.00 years) for cases. Males were 55.94% of the total population and 51.32% of all cases. There were four outbreaks of chickenpox across Elliniko (n = 1), Malakasa (n = 2), and Raidestos (n = 1) camps. The odds of chickenpox when controlling for age and sex was lower for Malakasa (OR = 0.46; 95% CI, 0.38 - 0.78) and Raidestos (OR = 0.36; 95% CI, 0.24 - 0.56) when compared Elliniko. Odds of chickenpox were comparable between Malakasa and Raidestos (OR = 1.49; 95% CI, 0.92 - 2.42). Across all camps, the highest incidence was among children zero-to-five years of age. The sex-specific incidence chickenpox was higher for males than females in Elliniko and Malakasa, while the incidence was higher among females in Raidestos.

CONCLUSION

As expected, individuals five years of age and under made up the majority of chickenpox cases. However, 12% of cases were teenagers or older, highlighting the need to consider atypical age groups in vaccination strategies and control measures. To support both host and displaced populations, it is important to consider risk-reduction needs for both groups. Including host communities in vaccination campaigns and activities can help reduce the population burden of disease for both communities.

Burden of chickenpox complications in Poland, 2006 to 2021: A comprehensive registry-based study

BackgroundChickenpox, a vaccine-preventable disease caused by the varicella zoster virus, generally presents with mild symptoms but can cause complications necessitating hospitalisation. In Poland, since 2009, vaccination has been obligatory for children up to 12 years of age who are particularly vulnerable to infection and for children in their vicinity.AimTo examine the burden of chickenpox complications and the trends of hospitalisation arising from these complications over time in the Polish population.MethodsData spanning 2006-21 were sourced from the Polish Infectious Diseases Surveillance System, the Nationwide General Hospital Morbidity Study and the Statistics Poland death registry. Standardised and age-specific incidence rates, hospital discharge rates and number of deaths because of chickenpox were calculated. Moreover, the joinpoint regression model was used to analyse trends of annual hospital discharge rates.ResultsOver the analysed timeframe, 25,804 hospitalisations and 52 deaths attributable to chickenpox complications were documented, and 1.0% of chickenpox cases required hospitalisation because of chickenpox. Age-standardised hospitalisation rates varied between 2.3 and 9.6 per 100,000 population. The analysis revealed no statistically significant trend in overall hospital discharge rates from chickenpox complications. However, a notable increase in hospitalisation rates was observed in children aged 0-4 and among inhabitants of rural areas, with annual percentage changes of 4.9% and 3.4% respectively.ConclusionsOur findings suggest that the implementation of a universal chickenpox immunisation programme, supported by health education, should be considered to reduce the number of hospitalisations and nearly eliminate deaths because of chickenpox.

Global Prevalence of Varicella-Associated Complications: A Systematic Review and Meta-Analysis

INTRODUCTION

Varicella (chickenpox) is an infectious disease caused by the varicella zoster virus affecting children, adolescents, and adults. Varicella symptoms are usually self-limiting; however, different complications with widespread and systemic manifestations can occur. This systematic literature review aims to explore and quantify varicella-associated complication rates.

METHODS

Two databases (Embase and MEDLINE), congress abstracts, and reference lists of systematic reviews were screened to identify evidence on varicella complications. Complications were identified and grouped into 14 clinically relevant categories. Proportional meta-analyses were conducted using a random-effects model and tests for heterogeneity and publication bias were performed. Subgroup, sensitivity, and meta-regression analyses were also conducted. A total of 78 studies, spanning 30 countries, were included in the meta-analysis.

RESULTS

Pooled prevalence was highest in severe varicella (22.42%; 95% confidence interval [CI] 10.13-37.77), skin-related complications (20.12%; 95% CI 15.48-25.20), and infection-related complications (10.03%; 95% CI 7.47-12.90). Cardiovascular (0.55%; 95% CI 0.08-1.33), genitourinary (1.17%; 95% CI 0.55-1.99), and musculoskeletal (1.54%; 95% CI 1.06-2.11) complications had the lowest pooled prevalence. The remaining complication categories ranged between 1% and 10%. Subgroup analysis showed that complications were more prevalent in children versus adults and in hospitalized patients versus outpatients. Meta-regression analysis found that no ecological level covariates were accurate predictors for the overall prevalence of varicella-associated complications. There was substantial heterogeneity and publication bias across all meta-analyses.

CONCLUSION

Results suggest that different types of varicella-associated complications could be frequent, impacting quality of life, and healthcare resource utilisation and budgets. These findings are crucial to raise awareness of the health and economic burden of varicella disease.

Healthcare resource use and costs of varicella and its complications: A systematic literature review

Varicella is a highly contagious disease caused by the varicella zoster virus (VZV). While the disease is usually mild, severe complications can occur requiring costly hospitalization. A thorough understanding of the healthcare resource use (HCRU) and costs of varicella is needed to inform health-economic models of preventive strategies. A systematic literature review was carried out to retrieve relevant publications between 1999 and 2021, reporting HCRU and cost outcomes for varicella and its complications. Data were extracted and stratified according to pre-specified age groups and complication categories. Costs were re-based to a $US2020 footing using both purchasing power parity and the medical component of consumer price indexes. Data were summarized descriptively due to high heterogeneity in study design and outcome reporting. Forty-four publications fulfilled the inclusion and exclusion criteria of which 28 were conducted in Europe, 6 in Middle East and Asia, 5 in South America, 3 in North America, and 2 in multiple regions. Primary healthcare visits accounted for 30% to 85% of total direct costs. Hospitalization costs varied between $1,308 and $38,268 per episode depending on country, complication type, and length of stay, contributing between 2% and 60% to total direct costs. Indirect costs, mostly driven by workdays lost, accounted for approximately two-thirds of total costs due to varicella. The management of varicella and related complications can lead to substantial HCRU and costs for patients and the healthcare system. Additional research is needed to further characterize the varicella-associated economic burden and its broader impact from a societal standpoint.

Impact of Varicella Immunization and Public Health and Social Measures on Varicella Incidence: Insights from Surveillance Data in Shanghai, 2013-2022

To evaluate the impact of a two-dose VarV program on varicella incidence among the whole population, considering the influence of public health and social measures (PHSMs), we extracted surveillance data on varicella cases during 2013-2022 in Minhang, Shanghai. Then, we estimated the incidence trend of varicella through interrupted time-series analyses and quantified the impact of the immunization program and PHSMs using Serfling regression. We also explored the associations between PHSMs and varicella cases. The implementation of the two-dose VarV strategy was followed by a significant decrease in varicella incidence (-1.84% per month). After one year of the program, varicella incidence was estimated at a 45.25% reduction, which was higher in children (59.12% and 54.09%) than in adults (19.49%). The decrease attributed to PHSMs was 31.26% during 2020-2022, and school closing was identified as the most relevant PHSM (b = -8.03 cases, r = -0.67 with a 1-week lag). These findings indicate that the two-dose immunization program has more effectively reduced the varicella incidence compared with the one-dose vaccine, and interventions like school closings are also encouraged to serve as supplementary measures to prevent varicella epidemics.

Prospective study of loss of health-related quality adjusted life years in children and their families due to uncomplicated and hospitalised varicella

INTRODUCTION AND AIMS

Although usually benign, varicella can lead to serious complications and sometimes long-term sequelae. Vaccines are safe and effective but not yet included in immunisation programmes in many countries. We aimed to quantify the impact on health-related quality of life (HRQoL) in terms of quality-adjusted life years (QALY) in children with varicella and their families, key to assessing cost-utility in countries with low mortality due to this infection.

METHODS

Children with varicella in the community and admitted to hospitals in Portugal were included over 18 months from January 2019. Children's and carers' HRQoL losses were assessed prospectively using standard multi-attribute utility instruments for measuring HRQoL (EQ-5D and CHU9D), from presentation to recovery, allowing the calculation of QALYs.

RESULTS

Among 109 families with children with varicella recruited from attendees at a pediatric emergency service (community arm), the mean HRQoL loss/child was 2.0 days (95 % CI 1.9-2.2, n = 101) (mean 5.4 QALYs/1000 children (95 % CI 5.3-6.1) and 1.3 days/primary carer (95 % CI 1.2-1.6, n = 103) (mean 3.6 QALYs /1000 carers (95 % CI 3.4-4.4). Among 114 families with children admitted to hospital because of severe varicella or a complication (hospital arm), the mean HRQoL loss/child was 9.8 days (95 % CI 9.4-10.6, n = 114) (mean 26.8 QALYs /1000 children (95 % CI 25.8-29.0) and 8.5 days/primary carer (95 % CI 7.4-9.6, n = 114) (mean 23.4 QALYs/1000 carers (95 % CI 20.3-26.2). Mean QALY losses/1000 patients were particularly high for bone and joint infections [67.5 (95 % CI 43.9-97.6)]. Estimates for children's QALYs lost using the CHU9D tool were well correlated with those obtained using EQ-5D, but substantially lower.

CONCLUSIONS

The impact of varicella on HRQoL is substantial. We report the first measurements of QALYs lost in hospitalised children and in the families of children both in the community and admitted to hospital, providing important information to guide vaccination policy recommendations.

A Dynamic Compartmental Model to Explore the Optimal Strategy of Varicella Vaccination: An Epidemiological Study in Jiangsu Province, China

Varicella (chickenpox) is highly contagious among children and frequently breaks out in schools. In this study, we developed a dynamic compartment model to explore the optimal schedule for varicella vaccination in Jiangsu Province, China. A susceptible-infected-recovered (SIR) model was proposed to simulate the transmission of varicella in different age groups. The basic reproduction number was computed by the kinetic model, and the impact of three prevention factors was assessed through the global sensitivity analysis. Finally, the effect of various vaccination scenarios was qualitatively evaluated by numerical simulation. The estimated basic reproduction number was 1.831 ± 0.078, and the greatest contributor was the 5-10 year-old group (0.747 ± 0.042, 40.80%). Sensitivity analysis indicated that there was a strong negative correlation between the second dose vaccination coverage rate and basic reproduction number. In addition, we qualitatively found that the incidence would significantly decrease as the second dose vaccine coverage expands. The results suggest that two-dose varicella vaccination should be mandatory, and the optimal age of second dose vaccination is the 5-10 year-old group. Optimal vaccination time, wide vaccine coverage along with other measures, could enhance the effectiveness of prevention and control of varicella in China.

The health and economic impact of switching vaccines in universal varicella vaccination programs using a dynamic transmission model: An Israel case study

Currently available health economic models for varicella infection are designed to inform the cost-effectiveness of universal varicella vaccination (UVV) compared with no vaccination. However, in countries with an existing UVV program, these models cannot be used to evaluate whether to continue with the current varicella vaccine or to switch to an alternative vaccine. We developed a dynamic transmission model that incorporates the historical vaccination program to project the health and economic impact of changing vaccination strategies. We applied the model to Israel, which initiated UVV in 2008 with a quadrivalent vaccine, MMRV-GSK, and switched to MMRV-MSD in 2016. The model was calibrated to pre-vaccination incidence data before projecting the impact of the historical and future alternative vaccination strategies on the clinical burden of varicella. Total costs and QALYs lost due to varicella infections were projected to compare continuing with MMRV-MSD versus switching to MMRV-GSK in 2022. Over a 50-year time horizon, continuing with MMRV-MSD reduced varicella incidence further by 64%, reaching 35 cases per 100,000 population by 2072, versus a 136% increase in incidence with MMRV-GSK. Continuing with MMRV-MSD reduced cumulative hospitalization and outpatient cases by 48% and 58% (vs. increase of 137% and 91% with MMRV-GSK), respectively. Continuing with MMRV-MSD resulted in 139 fewer QALYs lost with total cost savings of 3% compared with switching to MMRV-GSK, from the societal perspective. In Israel, maintaining the UVV strategy with MMRV-MSD versus switching to MMRV-GSK is projected to further reduce the burden of varicella and cost less from the societal perspective.

Cost effectiveness and budget impact of universal varicella vaccination in Russia

This economic evaluation assesses the cost-effectiveness and budget impact of introducing a two-dose varicella vaccine in the Russian national immunization program. A static Markov model followed a simulated 2019 Russian cohort over its lifetime and compared outcomes and costs of three varicella vaccination strategies: strategy I (doses given at 12 and 15 months of age), strategy II (doses given at 1 year and 6 years of age), and a no vaccination scenario. Inputs on age-dependent clinical pathways, associated costs, and related health outcomes were collected from national sources and published literature. Results are presented as incremental cost-effectiveness ratio (ICER) from the healthcare payer and societal perspective over the lifetime of the birth cohort and the budget impact over a 10 years' time horizon. Vaccination strategies I and II resulted in an ICER of approximately 1.7 million rubles per quality-adjusted life years gained from the healthcare payer perspective and were cost-saving from the societal perspective. From the healthcare payer perspective, the costs per varicella case averted were 5,989 and 7,140 rubles per case for strategies I and II, respectively. However, from the societal perspective, vaccination is a dominant strategy and the budget impact analysis shows significant healthcare savings over 10 years, with strategy I realizing savings of ~2 billion rubles more than strategy II. From a public health impact perspective, varicella vaccination of children at 12 and 15 months of age through the Russian NIP is expected to be cost-effective with an affordable budget impact compared to no vaccination.

Relative efficacy of varicella vaccines: network meta-analysis of randomized controlled trials

OBJECTIVE

Although varicella vaccination is highly effective, no head-to-head randomized controlled trials (RCTs) have compared the efficacy of different vaccine formulations. This study assessed the relative efficacy of different varicella vaccines using network meta-analysis (NMA).

METHODS

We estimated the relative efficacies of varicella vaccines and dosing regimens from RCTs using Bayesian NMA. Modeling-based time-series NMA (MBNMA) was performed, accounting for differences in time since vaccination, to extrapolate long-term vaccine efficacy (VE).

RESULTS

Eight RCTs were included based on systematic review of biomedical databases. Efficacy data were reported for four varicella-containing vaccines: Varivax (V-MSD, one and two dose), Varilrix (V-GSK, one dose), Priorix-Tetra (MMRV-GSK, one dose), and Sinovac (V-Sinovac, one dose). All varicella vaccines were effective versus no vaccination. Two-dose V-MSD (98.29%, 95% credible interval [CrI] 96.08-99.23) showed significantly higher VE versus all one-dose varicella-containing vaccines, but no significant difference versus two-dose MMRV-GSK (95.19%, 95% CrI 90.3-97.63). Two-dose MMRV-GSK showed higher VE than one-dose V-GSK (66.47%; 95% CrI 43.02-79.43), but no significant differences in VE versus one-dose V-MSD or one-dose V-Sinovac. In one-dose comparisons, V-MSD showed significantly higher VE (93.09%, 95% CrI 89.13-95.96) than V-GSK, but no significant difference versus V-Sinovac (89.22%; 95% CrI 67.1-96.5). MBNMA indicated that protection against varicella was sustained without waning over the 10 year follow-up.

CONCLUSIONS

Our study reported higher VE for two-dose V-MSD and MMRV-GSK. Among one-dose formulations, one-dose V-MSD was more efficacious than one-dose V-GSK. Policymakers should take into consideration differences in VE when implementing one- versus two-dose strategies in universal vaccination programs.

The Long-Term Clinical and Economic Impact of Universal Varicella Vaccination in Slovenia

Background: Despite the substantial burden of varicella infection, Slovenia does not currently have a universal varicella vaccination (UVV) program. We modeled the long-term clinical and economic impact of implementing 2-dose UVV strategies compared with no vaccination in Slovenia. Methods: A previously published dynamic transmission model was adapted to the demographics, varicella seroprevalence, herpes zoster incidence, and contact patterns in Slovenia. Six 2-dose UVV strategies, vs no vaccination, were considered over a 50-year period, including monovalent vaccination (Varivax^® [V-MSD] or Varilrix^® [V-GSK]) at ages 12 and 24 months, or monovalent vaccination at 15 months followed by monovalent or quadrivalent vaccination (ProQuad^® [MMRV-MSD] or Priorix- Tetra^® [MMRV-GSK]) at 5.5 years. Costs, quality-adjusted life-years, and incremental cost-effectiveness ratios vs no vaccination were calculated to assess the economic impact of each strategy from payer and societal perspectives. Results: The incidence of varicella infection was estimated as 1228 per 100 000 population in the absence of UVV. Over 50 years, depending on vaccination strategy, UVV reduced varicella cases by 77% to 85% and was associated with substantial reductions in varicella deaths (39%-44%), outpatient cases (74%-82%), and hospitalizations (74%-82%). The greatest reductions were predicted with V-MSD (15 months/5.5 years) and V MSD/MMRV-MSD (15 months/5.5 years). Discussion: All 2-dose UVV strategies were cost-effective compared with no vaccination from payer and societal perspectives, with V-MSD (15 months/5.5 years) being the most favorable from both perspectives. Conclusion: Policymakers should consider implementing UVV to reduce the burden of varicella disease in Slovenia.

PEPtalk 3: oral aciclovir is equivalent to varicella zoster immunoglobulin as postexposure prophylaxis against chickenpox in children with cancer - results of a multicentre UK evaluation

OBJECTIVE

To compare the occurrence of chickenpox in children with cancer who received varicella immunoglobulin (VZIG) or aciclovir as postexposure prophylaxis (PEP).

DESIGN

Prospective multicentre service evaluation of children with cancer who received either VZIG or aciclovir as PEP following significant exposure to varicella zoster virus (VZV) over a 24-month period from May 2018.

SETTING

Data were collected from 9 UK Paediatric Oncology Primary Treatment Centres.

PATIENTS

Children under 16 years old with a diagnosis of cancer and/or previous haematopoietic stem cell transplant who were VZV seronegative at exposure and/or diagnosis and received PEP following significant VZV exposure.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of breakthrough varicella within 6 weeks of VZV exposure and treatment with PEP.

RESULTS

A total of 105 eligible patients were registered with a median age of 4.9 years (range 1.1-10.5 years). Underlying diagnoses were acute leukaemia (64), solid tumours (22), Langerhans cell histiocytosis (9), central nervous system (CNS) tumours (8) and other (2). Aciclovir was received by 86 patients (81.9%), 18 received VZIG (17.1%) and 1 valaciclovir (0.9%). There were seven reported break-through VZV infections in 103 patients at follow-up (7/103, 6.8%). Clinical VZV developed in 5/84 of the aciclovir group (6.0%, 95% CI 2.0 to 13.3) and 2/18 of VZIG group (11.1%, 95% CI 1.4 to 34.7). All breakthrough infections were either mild (5/7) or moderate (2/7) in severity.

CONCLUSION

Aciclovir is a safe and effective alternative to VZIG as VZV PEP in children with cancer and should be considered as standard of care.

Primary Varicella or Herpes Zoster? An Educational Case Report From the Primary Care Clinic

Varicella-zoster virus is a pathogenic virus that can present itself as a primary infection or secondary infection, also known as herpes zoster. Recently, there has been a re-emergence of this vaccine-preventable disease due to gaps in vaccination. Primary varicella in immunocompetent adults is highly uncommon, and it could result in severe complications within this population. Given this delicate scenario, family physicians should be well trained to recognize the characteristic cutaneous lesions of varicella and dictate adequate management for these patients to obtain the best possible outcome and prevent life-threatening complications.

We present the case of a 43-year-old immunocompetent woman with the onset of a generalized pruritic dermatosis characterized primarily by the presence of macules, vesicles, and crusts. The patients' lesions were compatible with primary varicella, and serological studies confirmed the diagnosis. Given the absence of acute complications in this individual, supportive treatment and close follow-up were the therapeutic modalities. This article focuses on the educational discussion of the primary differential diagnosis, evaluation for possible complications, and management of this uncommon clinical scenario. We also reinforce the importance of immunization in preventing re-emergent diseases as a critical element within primary care management.

Randomised controlled trial showed long-term efficacy, immunogenicity and safety of varicella vaccines in Norwegian and Swedish children

AIM

Several countries, such as Norway and Sweden, have not implemented universal varicella vaccination. We present data for Norway and Sweden that were generated by a paediatric multi-country Phase III study over a 10-year period. This assessed the efficacy, antibody persistence and safety of two varicella vaccines containing the same Oka strain.

METHODS

This was an observer-blind, controlled trial conducted in 10 European countries. Children aged 12-22 months (n = 5803) were randomised 3:3:1 and vaccinated between 1 September 2005 and 10 May 2006. The two-dose group received two tetravalent measles-mumps-rubella-varicella vaccine doses. The one-dose group received one monovalent varicella vaccine dose after a measles-mumps-rubella vaccine dose. Control group participants received two measles-mumps-rubella vaccine doses. Main study outcomes were vaccine efficacy against confirmed varicella cases and incidence of adverse events.

RESULTS

Vaccine efficacy in the two-dose group was ≥92.1% in both Norwegian and Swedish children compared to 72.3% in Norway and 58.0% in Sweden in the one-dose group. Incidences of adverse events and serious adverse events were similar in the Norwegian and Swedish study populations.

CONCLUSION

Consistent with overall study results, high efficacy against varicella and acceptable safety profiles of the two varicella vaccines were observed in Norwegian and Swedish populations. These findings highlight the benefits of varicella vaccines, particularly when administered as a two-dose schedule.

Economic burden of varicella in Europe in the absence of universal varicella vaccination

Background

Though the disease burden of varicella in Europe has been reported previously, the economic burden is still unknown. This study estimated the economic burden of varicella in Europe in the absence of Universal Varicella Vaccination (UVV) in 2018 Euros from both payer (direct costs) and societal (direct and indirect costs) perspectives.

Methods

We estimated the country specific and overall annual costs of varicella in absence of UVV in 31 European countries (27 EU countries, plus Iceland, Norway, Switzerland and the United Kingdom). To obtain country specific unit costs and associated healthcare utilization, we conducted a systematic literature review, searching in PubMed, EMBASE, NEED, DARE, REPEC, Open Grey, and public heath websites (1/1/1999–10/15/2019). The number of annual varicella cases, deaths, outpatient visits and hospitalizations were calculated (without UVV) based on age-specific incidence rates (Riera-Montes et al. 2017) and 2018 population data by country. Unit cost per varicella case and disease burden data were combined using stochastic modeling to estimate 2018 costs stratified by country, age and healthcare resource.

Results

Overall annual total costs associated with varicella were estimated to be €662,592,061 (Range: €309,552,363 to €1,015,631,760) in Europe in absence of UVV. Direct and indirect costs were estimated at €229,076,206 (Range €144,809,557 to €313,342,856) and €433,515,855 (Range €164,742,806 to €702,288,904), respectively. Total cost per case was €121.45 (direct: €41.99; indirect: €79.46). Almost half of the costs were attributed to cases in children under 5 years, owing mainly to caregiver work loss. The distribution of costs by healthcare resource was similar across countries. France and Germany accounted for 49.28% of total annual costs, most likely due to a combination of high numbers of cases and unit costs in these countries.

Conclusions

The economic burden of varicella across Europe in the absence of UVV is substantial (over 600 M€), primarily driven by caregiver burden including work productivity losses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12343-x.

Has Clinical and Epidemiological Varicella Burden Changed over Time in Children? Overview on Hospitalizations, Comorbidities and Costs from 2010 to 2017 in Italy

According to WHO estimates, varicella disease is responsible of a worldwide significant burden in terms of hospitalizations, complications, and deaths, with more than 90% of cases under 12 years old. This study aims at evaluating the clinical, epidemiological, and economic burden of varicella in Ligurian children, about comorbidities, organizational variables, and vaccination coverages from 2010 to 2017, in terms of Emergency Department accesses and hospitalizations. The overall hospitalization rate was 179.76 (per 100,000 inhab.), with a gradual but significant decline since 2015, when universal varicella vaccination was introduced in Liguria (p < 0.0001). The risk of being hospitalized for complicated varicella in subjects with at least one comorbidity was significantly higher than in subjects without comorbidities (p = 0.0016). The economic analysis showed higher costs in subjects with complicated varicella who were 0-3 years old. This age group showed higher costs also considering extra-hospital costs for both outpatient procedures and pharmaceutical costs (p < 0.0001). The results confirm the relevant burden of varicella, especially in the 0-3 age group and in children with comorbidities. Thus, vaccination with the achievement of adequate vaccination coverages is confirmed to be a necessary control strategy to reduce hospitalizations and associated complications with important economic benefits.

Epidemiological Impact and Cost-Effectiveness of Varicella Vaccination Strategies in the United Kingdom

Background

Despite the burden of varicella, there is no universal varicella vaccination (UVV) program in the United Kingdom (UK) due to concerns that it could increase herpes zoster (HZ) incidence. We assessed the cost-utility of a first-dose monovalent (varicella [V]) or quadrivalent (measles-mumps-rubella-varicella [MMRV]) followed by a second-dose MMRV UVV program. GSK and MSD varicella-containing vaccines (VCVs) were considered.

Methods

Dynamic transmission and cost-effectiveness models were adapted to the UK. Outcomes measured included varicella and HZ incidences and the incremental cost-utility ratio (ICURs) over a lifetime horizon. Payer and societal perspectives were evaluated.

Results

The impact of V-MMRV and MMRV-MMRV UVV programs on varicella incidence was comparable between both VCVs at equilibrium. HZ incidence increased by 1.6%–1.7% over 7 years after UVV start, regardless of the strategies, then decreased by >95% at equilibrium. ICURs ranged from £5665 (100 years) to £18 513 (20 years) per quality-adjusted life-year (QALY) gained with V-MMRV and from £9220 to £27 101 per QALY gained with MMRV-MMRV (payer perspective). MMRV-MMRV was cost-effective in the medium- and long-terms with GSK VCV and only cost-effective in the long term with MSD VCV at a £20 000 per QALY gained threshold. Without the exogenous boosting hypothesis, HZ incidence decreased through UVV implementation. ICURs were most sensitive to discount rates and MMRV price.

Conclusions

A 2-dose UVV was demonstrated to be a cost-effective alternative to no vaccination. With comparable effectiveness as MSD VCV at lower costs, GSK VCV may offer higher value for the money.

Phase 3, open-label, Russian, multicenter, single-arm trial to evaluate the immunogenicity of varicella vaccine (VARIVAX™) in healthy adults

Varicella (chickenpox) is a common, highly contagious disease caused by primary infection with varicella zoster virus (VZV). Adults typically experience more severe symptoms than children and have a higher risk of developing complications. Stage 1 of this Phase 3 open-label study enrolled healthy adults in Russia aged 18-75 years without a clinical history of varicella infection. Eligible participants (n = 50) were administered 2 doses of VARIVAX™ (Varicella Virus Vaccine Live [Oka/Merck]) 0.5 mL 6 weeks apart. For participants seronegative at baseline (VZV antibody titer <1.25 glycoprotein enzyme-linked immuno-sorbent assay [gpELISA] units/mL), immunogenicity was assessed by seroconversion (VZV antibody titer ≥5 gpELISA units/mL) and assessment of geometric mean titers of VZV antibody as measured by gpELISA 6 weeks after Dose 2. For VZV seropositive participants at baseline (VZV antibody titer ≥1.25 gpELISA units/mL), immunogenicity was assessed by geometric mean fold rise in antibody titer and percentage of participants with a ≥ 4-fold rise in antibody titer 6 weeks after Dose 2. A Vaccine Report Card was used to record solicited and unsolicited adverse events through 42 days post-vaccination. All participants who were seronegative (n = 26) at baseline demonstrated seroconversion 6 weeks after Dose 2. Among participants who were seropositive at baseline (n = 23), 60.9% had a ≥4-fold rise in antibody titer 6 weeks after Dose 2. Vaccination was generally well tolerated, with no new safety signals identified. Administration of 2 doses of VARIVAX in adults in Russia results in acceptable immune responses with safety data consistent with the licensed product (Clinicaltrials.gov identifier: NCT03843632).

Clinical and economic impact of universal varicella vaccination in Norway: A modeling study

BACKGROUND

Norway has not implemented universal varicella vaccination, despite the considerable clinical and economic burden of varicella disease.

METHODS

An existing dynamic transmission model of varicella infection was calibrated to age-specific seroprevalence rates in Norway. Six two-dose vaccination strategies were considered, consisting of combinations of two formulations each of a monovalent varicella vaccine (Varivax® or Varilrix®) and a quadrivalent vaccine against measles-mumps-rubella-varicella (ProQuad® or PriorixTetra®), with the first dose given with a monovalent vaccine at age 15 months, and the second dose with either a monovalent or quadrivalent vaccine at either 18 months, 7 or 11 years. Costs were considered from the perspectives of both the health care system and society. Quality-adjusted life-years saved and incremental cost-effectiveness ratios relative to no vaccination were calculated. A one-way sensitivity analysis was conducted to assess the impact of vaccine efficacy, price, the costs of a lost workday and of inpatient and outpatient care, vaccination coverage, and discount rate.

RESULTS

In the absence of varicella vaccination, the annual incidence of natural varicella is estimated to be 1,359 per 100,000 population, and the cumulative numbers of varicella outpatient cases, hospitalizations, and deaths over 50 years are projected to be 1.81 million, 10,161, and 61, respectively. Universal varicella vaccination is projected to reduce the natural varicella incidence rate to 48-59 per 100,000 population, depending on the vaccination strategy, and to reduce varicella outpatient cases, hospitalizations, and deaths by 75-85%, 67-79%, and 75-79%, respectively. All strategies were cost-saving, with the most cost-saving as two doses of Varivax® at 15 months and 7 years (payer perspective) and two doses of Varivax® at 15 months and 18 months (societal perspective).

CONCLUSIONS

All modeled two-dose varicella vaccination strategies are projected to lead to substantial reductions in varicella disease and to be cost saving compared to no vaccination in Norway.

Clinically- versus serologically-identified varicella: A hidden infection burden. A ten-year follow-up from a randomized study in varicella-endemic countries

Varicella-zoster virus (VZV) infections cause a substantial disease burden, which is underestimated due to incomplete reporting data and lack of serological surveillance. In this post-hoc analysis of a randomized, Phase IIIb clinical trial (NCT00226499) with a ten-year follow-up period, we report anti-VZV antibody levels and persistence in non-vaccinated children, as a varicella infection estimate in ten European countries with endemic varicella. The present analysis specifically focuses on clinical and serological data from the control group, which included 827 healthy participants aged 12–22 months who received two doses of measles-mumps-rubella (MMR) vaccine. The per-protocol cohort included 744 children for whom varicella occurrence was evaluated by clinical definitions, epidemiological links and PCR test outcomes. Anti-VZV antibody levels were assessed by ELISA. The primary objective of this analysis was to correlate varicella occurrence with anti-VZV antibody levels. Varicella was confirmed in 47% of MMR recipients. Among participants without reported varicella, the percentage of anti-VZV seropositive children increased to 75% and average anti-VZV antibody concentrations increased to 250 mIU/mL at year ten after vaccination, suggesting infection or exposure. An eight-fold increase in anti-VZV antibody concentrations between two consecutive visits, which is also observed after confirmed varicella, was detected in 37% of these participants during the follow-up period. About one-third of children not vaccinated against varicella and not diagnosed with varicella developed an anti-VZV immune response, suggesting subclinical varicella occurrence. Longitudinal studies combining serology and disease incidence are necessary to reliably estimate total varicella burden of infection.

Acceptance of varicella vaccination

Varicella is a common vaccine-preventable disease that usually presents in children as a mild infection; however, severe complications also occur. The burden of varicella is significant in the terms of incidence, complication, and hospitalization rate related to varicella and economic disease burden. Despite the evidence of overall positive effects of varicella vaccination, there are great differences in the implementation of varicella vaccination and in the uptake of the vaccine from country to country. Improving acceptance of varicella vaccination on the national and on the individual level would decrease the burden of the disease on the health of children and on health-care resources. In studies determining factors of parental acceptance of varicella vaccination questions specific for varicella vaccination were highlighted. Addressing these issues with open, evidence based communication is important to improve and maintain the trust of the public in varicella vaccination.

Health Impact and Cost-effectiveness Assessment for the Introduction of Universal Varicella Vaccination in Switzerland

BACKGROUND

Varicella, caused by the varicella-zoster virus, is a highly contagious infectious disease with substantial health and economic burden to society. Universal varicella vaccination (UVV) is not yet recommended by the Swiss National Immunization Program, which instead recommends catch-up immunization for children, adolescents and adults 11-40 years of age who have no reliable history of varicella or are varicella-zoster virus-IgG seronegative. The objective of this study was to perform an assessment of health impact and cost-effectiveness comparing UVV with current practice and recommendations in Switzerland.

METHODS

A dynamic transmission model for varicella was adapted to Switzerland comparing 2 base-case schedules (no infant vaccination and 10% coverage with infant vaccination) to 3 different UVV schedules using quadrivalent (varicella vaccine combined with measles-mumps-rubella) and standalone varicella vaccines administered at different ages. Modeled UVV coverage rates were based on current measles-mumps-rubella coverage of approximately 95% (first dose) and 90% (second dose). Direct medical costs and societal perspectives were considered, with cost and outcomes discounted and calculated over a 50-year time horizon.

RESULTS

UVV would reduce the number of varicella cases by 88%-90%, hospitalizations by 62%-69% and deaths by 75%-77%. UVV would increase direct medical costs by Swiss Franc (CHF) 39-49 (US $43-54) per capita and costs from a societal perspective by CHF 32-40 (US $35-44). Incremental quality-adjusted life-years per capita increased by 0.0012-0.0014. Incremental cost-effectiveness ratios for the UVV schedules versus the base-case were CHF 31,194-35,403 (US $34,452-39,100) per quality-adjusted life-year from the direct medical cost perspective and CHF 25,245-29,552 (US $27,881-32,638) from the societal perspective.

CONCLUSIONS

UVV appears highly effective and cost-effective when compared with current clinical practice and recommendations in Switzerland from both a direct medical costs perspective and societal perspective.

Ten-year follow-up on efficacy, immunogenicity and safety of two doses of a combined measles-mumps-rubella-varicella vaccine or one dose of monovalent varicella vaccine: Results from five East European countries

BACKGROUND

We assessed the 10-year efficacy, immunogenicity and safety of two doses of a combined measles-mumps-rubella-varicella vaccine (MMRV) or one dose of a monovalent varicella vaccine (V) in children from Czech Republic, Lithuania, Poland, Romania and Slovakia.

METHODS

This was a phase IIIB follow-up of an observer-blind, randomized, controlled trial (NCT00226499). In phase A, healthy children aged 12-22 months from 10 European countries were randomized in a 3:3:1 ratio to receive two doses of MMRV (MMRV group), one dose of MMR followed by one dose of V (MMR + V group), or two doses of MMR (MMR; control group), 42 days apart. Vaccine efficacy (VE) against varicella (confirmed by viral DNA detection or epidemiological link and clinical assessment) was calculated with 95% confidence intervals using Cox proportional hazards regression model. Immunogenicity was assessed as seropositivity rates and geometric mean concentrations (GMCs). Solicited and unsolicited adverse events (AEs) and serious AEs (SAEs) were recorded.

RESULTS

A total of 3705 children were vaccinated (1590, MMRV group; 1586, MMR + V group; 529, MMR group). There were 663 confirmed varicella cases (47, MMRV group; 349, MMR + V group; 267, MMR group). VE ranged between 95.4% (Lithuania) and 97.4% (Slovakia) in the MMRV group and between 59.3% (Lithuania) and 74% (Slovakia) in the MMR + V group. At year 10, seropositivity rates were 99.5%-100% in the MMRV group, 98%-100% in the MMR + V group and 50%-100% in the MMR control group, and the anti-VZV antibody GMCs were comparable between MMRV and MMR + V groups. The occurrence of solicited and unsolicited AEs was similar across groups and no SAE was considered as vaccination-related. No new safety concerns were identified.

CONCLUSIONS

Our results indicated that two doses of varicella zoster virus-containing vaccine provided better protection than one dose against varicella and induced antibody responses that persisted 10 years post-vaccination.

Seroprevalence survey for Varicella among healthcare workers and medical students in Italy

Varicella is a potentially serious infectious disease caused by Varicella-Zoster Virus (VZV). In Italy childhood varicella vaccine have gradually introduced into national immunization program since 2003 and from 2017 a two-doses schedule has been stated nationally for all newborns and has become compulsory for school attendance. VZV exposures among healthcare workers (HCWs) and patients can be really dangerous and expensive. According to Centers of Disease Control and Italian national immunization plan health care, institutions should verify that all HCWs have clear evidence of immunity to VZV and should ensure that susceptible subjects will receive 2 doses of VZV vaccine. Currently, the vaccination of HCWs is not compulsory in Italy and the risk of varicella infection among these subjects is not well known. We evaluated the clinical records of 840 HCWs (256 male and 584 female) who underwent the annual occupational screening, from 1st January to 31st August 2018. HCWs were divided into three subgroups according to their age: 18-30, 31-40, and over 40 years old. We compared the mean values of IgG-specific antibodies between the age group through analysis of variance (ANOVA). A total of 784 (93.33%) HCWs were protected for VZV IgG antibodies level. There wasn't a significant difference between male and female while was found between age group (P < 0.001). Protection levels for varicella are inadequate among HCWs. Despite the epidemiology of varicella in general population has changed with the implementation of the childhood varicella vaccination program transmission of VZV in hospitals is still a serious problem, so it is necessary to increase prevention activities in these settings, including vaccination.

Epidemiology of varicella and effectiveness of varicella vaccine in Hangzhou, China, 2019

Background: The varicella vaccine (VarV) is not included in the national childhood immunization schedules in China, although 2-dose VarV (VarV2) were recommended for children at 1 and 4 years of age in Hangzhou since 2014. However, the reported incremental vaccine effectiveness (VE) of VarV2 varies widely among studies. We described the epidemiological characteristics of varicella in Hangzhou, assessed the VE of VarV, so as to provide scientific evidence on optimization and adjustment of immunization strategies for varicella prevention in China. Methods: All varicella cases diagnosed in a hospital in Hangzhou are reported to China Information System for Disease Control and Prevention (CISDCP). The demographic information of reported varicella cases onset from January 1 to December 31, 2019 was extracted from CISDCP on Jan 31, 2020. The demographic information was obtained from the information system of the National Center for Disease Prevention and Control. We conducted a 1:1 matched case-control study to assess the effectiveness of VarV. Participant data were collected with standardized questionnaires. VarV vaccination status was checked by using Hangzhou Immunization Information System (HZIIS). Results: A total of 11,813 varicella cases were reported in Hangzhou, China, 2019, without any death. Annual estimated incidence of varicella was 120 cases per 100,000 populations in 2019. The overall estimated incidence rate of varicella was high, especially for persons aged 10-19 years old and in suburb areas. The seasonal pattern was apparent, mostly due to the cases among students and children in kindergarten. In total, 218 varicella cases and 218 matched controls were included for evaluating the VE of VarV. VarV vaccination produced a high level of protection against varicella, while VE of VarV2 was even better. VE of VarV1 was 91.0% (95%CI: 81.6%-95.8%), and VE was 98.0% (95.5%-99.2%) for VarV2. Conclusion: Continuous monitoring and management of varicella cases is necessary, especially in those endemic areas, high-risk populations, and peak periods; a 2-dose VarV strategy is highly recommended, and relevant health institutions should consider the inclusion of VarV in the national immunization program to better control varicella epidemic and reduce the burden of varicella.

Attitudes towards varicella vaccination in parents and paediatric healthcare providers in Hungary

BACKGROUND

Varicella vaccination is important in prevention of childhood infection. Aim of this cross-sectional study was to survey attitudes and determinants of support or refusal of varicella vaccination in parents and in paediatric healthcare professionals, mainly health visitors in Hungary prior to the introduction of this vaccine in National Immunization Program in 2019.

METHODS

Between October 2018 and February 2019, 1042 parents and 198 healthcare professionals completed a self-administered anonymous questionnaire regarding sociodemographic background, knowledge and attitudes towards varicella vaccination, and reasons for non-vaccination.

RESULTS

From the participating parents 53.3% have vaccinated at least one of their children. Vaccination rate was significantly higher in families with <3 children, living in the capital, among those who have seen complications of varicella and among parents with university degree. Most important positive determinant was recommendation of the vaccine by healthcare professionals: 77.8% of parents accepted vaccination when recommended by the paediatrician, despite the cost of the vaccine, whereas only 17.3% of parents vaccinated their children when the vaccine was not recommended by paediatrician. Most important reasons for non-vaccination was finding the vaccine unnecessary, concerns regarding side effects, and not believing in the vaccine's effectiveness. Among paediatric healthcare professionals, support rate of universal varicella vaccination was 76.3%. Support rate was higher among those who have seen complications of varicella more often and those who consider varicella a severe infection. Reasons of professionals who do not support universal varicella vaccination were similar to those of vaccine hesitant parents. Practice of intentional exposure of non-immune child to infected ones still exist.

CONCLUSIONS

Educational programs are needed for parents and health visitors to address concerns regarding vaccination. Paediatricians are the most trusted source of information for parents hence they have a significant responsibility and parents likely follow their recommendations.

Specific Varicella-Related Complications and Their Decrease in Hospitalized Children after the Introduction of General Varicella Vaccination: Results from a Multicenter Pediatric Hospital Surveillance Study in Bavaria (Germany)

BACKGROUND

Universal varicella vaccination (UVV) for children introduced in Germany in 2004 resulted in a significant overall decline of varicella-related hospitalizations (VRHs). We investigated the incidence of specific types of varicella-related complications (VRCs) in hospitalized children and the impact of UVV on VRCs during the first 7 years of UVV.

METHODS

Children < 17 years of age hospitalized with an ICD-10-based (International Classification of Diseases, 10th Revision) discharge diagnosis of varicella were identified as VRH in pediatric hospitals in Bavaria by annual standardized data queries of the hospital databases (2005-2011). For each VRH, the hospitals reported basic demographic data, duration of hospital stay, all diagnostic and procedural codes, and outcome. VRCs were reported overall, per year, and by immune status. Complication rates were calculated as mean number per complication category per hospital and per year; VRC trends over time were assessed by linear regression.

RESULTS

Between 78% (2005) and 61% (2011) of Bavarian hospitals participated and reported a total of 1263 VRHs. Specific VRCs were reported in 954 (76%) children. Complication rates per hospital and year decreased from 6.7 [95% confidence interval (CI): 5.1-8.3] in 2005 to 1.5 (95% CI: 0.8-2.3) in 2011, with the strongest reduction of 90% in children < 5 years of age from 5.3 (95% CI: 4.0-6.6) in 2005 to 0.5 (95% CI: 0.1-0.9) in 2011. Significant decreases were observed for children with upper respiratory tract (URT, by 97%), lower respiratory tract (LRT, by 90%), skin (by 81%), gastrointestinal (by 78%), and neurologic (by 65%) VRCs. Forty-eight children with VRCs were immunocompromised; their annual rate decreased by 87%.

DISCUSSION

Corresponding to increasing varicella vaccination coverage in the population, the incidence of VRC decreased by 77% from 2005 to 2011, with the most substantial decrease in the target group for UVV.

CONCLUSION

Within 7 years, UVV in Germany led to a decrease of about 77% of all types of VRCs, with the highest reductions observed for VRCs of the respiratory tract.

Varicella zoster virus vaccines: an update

Varicella zoster virus (VZV) is the etiological agent of varicella, a highly infectious, self-limiting disease with serious complications. The decline in cell-mediated immunity (CMI) that occurs with aging or immunodepression causes a reactivation of the latent VZV as herpes zoster (HZ). Prevention of VZV through varicella vaccination strategies allows to avoid the primary infection in newborns and susceptible subjects. Available monovalent and combined VZV vaccines are effective, safe and generally well tolerated. Universal varicella vaccination has significantly impacted on incidence, complications and deaths related to this disease. Prevention of HZ through vaccination is a priority to avoid the significant burden of its incidence and complications. Currently two HZ vaccines are available. The recombinant zoster vaccine (RZV), approved by the FDA in 2017 and Zoster Vaccine Live (ZVL) licensed in the United States by the FDA in 2006. The advisory committee on immunization practices (ACIP) preferentially recommends RZV. ZVL remains an option for prevention of HZ in immunocompetent adults aged ≥60 years, although the CMI tends to wane a few years after vaccination.

Epidemiological and clinical characteristics and the approach to infant chickenpox in primary care

Chickenpox is not common in the first year of life (infant varicella) and there is a lack of data on its presentation, especially in primary care. A year-long observational study (July 2015-2016) carried out by a research network of primary care pediatricians throughout Spain.Two hundred and sixty-four pediatricians gathered data from 358 cases of clinically diagnosed chickenpox in infants. The illness was considered mild in 78% of infants < 7 months compared to 65% in those aged 7 to 12 months (p = 0.0144). Fever (46%) was present in 35% of children ≤ 6 months compared to 55% in older children (p = 0.0005). The number of skin lesions was > 50 in 35% of children ≤ 6 months old compared to 47% in > 7 months (p = 0.0273). From the 2% of hospitalized children 86% were younger than 7 months. Oral antiviral treatment was given in 33% of cases ≤ 6 months compared to 18% in older patients (p = 0.0023). Doubts about administering the chickenpox vaccine at a later date were expressed by 18% of pediatricians.Conclusion: Chickenpox is considered benign, having a mild effect on most infants. There is less clinical effect in infants ≤ 6 months although this age group is hospitalized more and is prescribed more antiviral treatment. There are doubts among pediatricians about the subsequent need for vaccination. What is Known: • Chickenpox is uncommon and of uncertain evolution in the first year of life • Hospital admissions for chickenpox are more frequent in the first year of life What is New: • The course of chickenpox in the first year of life is mild, especially in infants younger than 7 months despite the fact they are hospitalized more and are treated more frequently with antivirals. Antivirals are prescribed to 1 in 4 children with chickenpox under 12 months of age. • Almost 50% of pediatricians recommend a subsequent vaccination against chickenpox especially if it occurs in the first 6 months of life.

Burden of varicella in the Asia-Pacific region: a systematic literature review

INTRODUCTION

Varicella is a highly contagious infection that can lead to serious complications, particularly in high-risk groups; however, it is vaccine preventable. Disease awareness and understanding of the disease burden can strongly influence vaccine coverage. This review provides insight into the current epidemiology and the importance of varicella from both public health and economic perspectives across the Asia-Pacific (APAC) region. Areas covered: A systematic literature review was conducted to identify studies on the incidence, seroprevalence, fatality rate and complication rate of varicella. Economic burden studies were also captured. Altogether, 125 studies were identified across the region; these were supplemented by government reports (gray data). Reported vaccine coverage varied from 2.8% to 97%; a key influencing factor was inclusion of the varicella vaccine in national immunization programs. In general, varicella incidence in the unvaccinated population was highest in children ≤5 years old and seroprevalence increased with age. Economic analyses highlighted the cost-saving potential of vaccination programs, especially from a societal perspective. Expert opinion: Varicella-related data varied greatly across the APAC region, highlighting the need to better understand the burden of varicella in this area, and particularly identified the need for better surveillance and reporting.

Burden of varicella in Central and Eastern Europe: findings from a systematic literature review

INTRODUCTION

Vaccination against varicella rapidly reduces disease incidence, resulting in reductions in both individual burden and societal costs. Despite these benefits, there is no standardization of varicella immunization policies in Europe, including countries in Central and Eastern Europe (CEE).

AREAS COVERED

This systematic literature review identified publications on the epidemiology of varicella, its associated health and economic burden, and vaccination strategies within the CEE region, defined as Albania, Bosnia-Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, Serbia, Slovakia, and Slovenia. Twenty-six studies were identified from a search of PubMed, Embase®, and MEDLINE® biomedical literature databases, supplemented by gray literature and country-specific/global websites.

EXPERT COMMENTARY

Limited information exists in published studies on the burden of varicella in CEE. The wide variability in incidence rates between countries is likely explained by a lack of consistency in reporting systems. Funded universal varicella vaccination (UVV) in CEE is currently available only in Latvia as a one-dose schedule, but Hungary together with Latvia are introducing a two-dose strategy in 2019. For countries that do not provide UVV, introduction of vaccination is predicted to provide substantial reductions in cases and rates of associated complications, with important economic benefits.

Protection against varicella with two doses of combined measles-mumps-rubella-varicella vaccine or one dose of monovalent varicella vaccine: 10-year follow-up of a phase 3 multicentre, observer-blind, randomised, controlled trial

BACKGROUND

The duration of protection provided by varicella vaccines is unclear. We assessed the 10-year vaccine efficacy of two doses of a combined measles-mumps-rubella-varicella vaccine (MMRV), one live attenuated varicella vaccine (V) dose given after one measles-mumps-rubella vaccine (MMR) dose (MMR + V), versus two MMR doses (control vaccine) for the prevention of confirmed varicella.

METHODS

This was a phase 3b follow-up of an observer-blinded, randomised, controlled trial. In phase a, children aged 12-22 months (at first vaccination) from Czech Republic (Czechia), Greece, Italy, Lithuania, Norway, Poland, Romania, Russia, Slovakia, and Sweden were randomly assigned by computer-generated randomisation list (3:3:1) to receive two doses of MMRV, one dose of MMR and one dose of varicella vaccine, or two doses of MMR, 42 days apart. Varicella cases were confirmed by detection of viral DNA, or epidemiological link and clinical assessment, by an independent data monitoring committee; disease severity was based on a modified Vázquez scale. Hazard ratios for MMRV and MMR + V versus MMR estimated in the per-protocol cohort using a Cox proportional hazards regression model were used to calculate vaccine efficacy and 95% CI. Serious adverse events were recorded throughout the study in all vaccinated children. Study objectives were secondary and descriptive. The trial is registered at ClinicalTrials.gov, number NCT00226499.

FINDINGS

Between Sept 1, 2005, and May 10, 2006, 5803 children (mean age 14·2 months, SD 2·5) were vaccinated. The per-protocol cohort included 2279 children from the MMRV group, 2266 from the MMR + V group, and 744 from the MMR group. From baseline to a median follow-up of 9·8 years, 76 (3%) children in the MMRV group, 469 (21%) in the MMR + V group, and 352 (47%) in the MMR group had varicella. Vaccine efficacy against all varicella was 95·4% (95% CI 94·0-96·4) for MMRV and 67·2% (62·3-71·5) for MMR + V; vaccine efficacy against moderate or severe varicella was 99·1% (97·9-99·6) for MMRV and 89·5% (86·1-92·1) for MMR + V. During phase b, serious adverse events were reported by 290 (15%) of 1961 children in the MMRV group, 317 (16%) of 1978 in the MMR + V group, and 93 (15%) of 641 in the MMR group. There were no treatment-related deaths.

INTERPRETATION

The 10-years vaccine efficacy observed, suggests that a two-dose schedule of varicella vaccine provided optimum long-term protection for the prevention of varicella by offering individual protection against all severities of disease and leading to a potential reduction in transmission, as observed in the US experience with universal mass vaccination.

FUNDING

GlaxoSmithKline Biologicals.

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.

Streptococcus pyogenes Endocarditis Associated With Varicella-Case Report and Review of the Literature

Infection with varicella zoster virus (VZV) is usually a benign and self-limiting disease. Serious complications by bacterial pathogens do occur, such as necrotising fasciitis (NF). One of the most important is Streptococcus pyogenes (or Group A Streptococcus, GAS), which colonizes epithelial surfaces, primarily of the throat and skin. In rare instances, varicella may also be associated with S. pyogenes endocarditis. Review of the literature reveals only 18 children with infective endocarditis (IE) caused by GAS since 1942. VZV as antecedent illness was found in five (28%). Fourteen (78%) had no pre-existing cardiac abnormalities. Death occurred in three (17%) children. Infective endocarditis with acute deterioration secondary to rupture of mitral valve chordae tendineae necessitating cardiac surgery has not been reported in the literature yet. We present this rare and instructive pediatric case and the results of a literature search on S. pyogenes endocarditis in children.

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.

Management of chickenpox in pregnant women: an Italian perspective

Chickenpox is a highly contagious disease caused by primary infection of varicella zoster virus (VZV). The disease is spread worldwide and is usually benign but, in some groups of population like pregnant women, can have a severe outcome. Due to a not optimal vaccination coverage, a relatively high number of childbearing-aged women in a European country such as Italy tested seronegative for VZV and so are currently at risk of acquiring chickenpox during pregnancy, especially if they live in contact with children for family or work reasons. Only few data are available about the risk of infection in this setting: the incidence of chickenpox may range from 1.5 to 4.6 cases/1000 childbearing females and from 1.21 to 6 cases/10,000 pregnant women, respectively. This review is aimed to focus on the epidemiology and the clinical management of exposure to chickenpox during pregnancy. Particular emphasis is given to the accurate screening of childbearing women at the time of the first gynecological approach - the females who tested susceptible to infection can be counseled about the risks and instructed on procedure should contact occur - and to the early prophylaxis of the at-risk exposure. Lastly, the achievement of adequate vaccination coverage of the Italian population remains a cornerstone in the prevention of chickenpox in pregnancy.

Impact of vaccination programs against measles, varicella and meningococcus C in Italy and in Tuscany and public health policies in the last decades

The World Health Organization (WHO) has established specific targets for control, elimination or eradication of some vaccine preventable infectious diseases, which were periodically updated. In Italy, WHO recommendations have been endorsed and implemented over time, through the national and regional health prevention plans. The aim of the study was to assess the impact of the immunization practices against measles, varicella and Neisseria meningitidis type C (Men C) in Italy and in Tuscany Region, during the last decades, by analyzing national and regional surveillance databases. Benefits of vaccination strategies were discussed from different points of view (clinical, epidemiological, economic, ethical, social and communicative). The implementation of measles, varicella and Men C vaccination, caused a considerable decrease of incidence rates over the years in Italy and in Tuscany too. However, in the last years, notifications of measles and Men C cases in subjects not targeted by immunization campaigns, in Italy and in Tuscany, are a cause for concern for public health and for the achievement of the elimination goals. Achieving and maintaining high vaccine coverage guarantees a decrease in the incidence of serious diseases and their clinical and economic consequences, but it is necessary to strengthen surveillance system of infectious diseases in order to monitor epidemiological trends. Moreover, outreach campaigns are necessary to raise awareness in the general population and create the culture of prevention with the same nationwide health goals for all.

Varicella zoster virus transmission dynamics in Vojvodina, Serbia

This study aimed at establishing baseline key epidemiological parameters for varicella zoster virus (VZV) infection in Vojvodina, Serbia, with the ultimate goal to quantify the VZV transmission potential in the population. Seroprevalence data generated during the first large cross-sectional VZV serosurvey were modelled, using a two-tiered modelling approach to calculate age-specific forces of infection (FOI), the basic reproduction number (R₀) and herd immunity threshold (H). Seroprevalence and modelling data were compared with corresponding pre-vaccination epidemiological parameters from 11 countries participating in the European Sero-Epidemiology Network 2 (ESEN2) project. Serbia fits into the general dynamic VZV transmission patterns in Europe in the pre-vaccine era, with estimated R₀ = 4.12, (95% CI: 2.69–7.07) and H = 0.76 (95% CI: 0.63–0.86). The highest VZV transmission occurs among preschool children, as evidenced by the estimation of the highest FOI (0.22, 95% CI: 0.11–0.34) in the 0.5–4 age group, with a peak FOI of 0.25 at 2.23 years. Seroprevalence was consistently lower in 5–14 year-olds, resulting in considerable shares of VZV-susceptible adolescents (7.3%), and young adults (6%), resembling the situation in a minority of European countries. The obtained key epidemiological parameters showed most intense VZV transmission in preschool children aged <4 years, justifying the consideration of universal childhood immunization in the future. National immunization strategy should consider programs for VZV serologic screening and immunization of susceptible groups, including adolescents and women of reproductive age. This work is an important milestone towards the evaluation of varicella immunization policy options in Serbia.

Post-varicella Arterial Ischemic Stroke in Denmark 2010 to 2016

BACKGROUND

Varicella, most often a benign disease of childhood, is associated with an increased risk of arterial ischemic stroke in children. The aim of the present study was to estimate the incidence of post-varicella arterial ischemic stroke in the Danish child population and describe clinical characteristics of children admitted with post-varicella arterial ischemic stroke.

METHODS

In the Danish National Patient Register, we identified inpatients 28 days to 16 years of age with a discharge diagnosis of stroke or cerebrovascular disease from 2010 to 2016. Medical files were reviewed, and children with arterial ischemic stroke and varicella infection less than 12 months before onset of symptoms were included.

RESULTS

We identified 15 children with arterial ischemic stroke and varicella less than 12 months before. In nine children, the diagnosis was confirmed by detection of varicella zoster virus DNA or varicella zoster virus immunoglobulin G in the cerebrospinal fluid. All children were previously healthy, the mean age was four years, and 67% were male. The median time from varicella rash to arterial ischemic stroke was 4.6 months. The most common location of arterial ischemic stroke was the basal ganglia, and affected vessels were most often in the anterior circulation. Fifty-three percent experienced neurological sequelae of varying degree.

CONCLUSIONS

In Denmark, where varicella vaccination is not part of the childhood vaccination program, the estimated risk of post-varicella arterial ischemic stroke was one case (including possible cases) per 26,000 children with varicella.

Varicella and herpes zoster vaccine development: lessons learned

INTRODUCTION

Before vaccination, varicella zoster virus (VZV), which is endemic worldwide, led to almost universal infection. This neurotropic virus persists lifelong by establishing latency in sensory ganglia, where its reactivation is controlled by VZV-specific T-cell immunity. Lifetime risk of VZV reactivation (zoster) is around 30%. Vaccine development was galvanised by the economic and societal burden of VZV, including debilitating zoster complications that largely affect older individuals. Areas covered: We describe the story of development, licensing and implementation of live attenuated vaccines against varicella and zoster. We consider the complex backdrop of VZV virology, pathogenesis and immune responses in the absence of suitable animal models and examine the changing epidemiology of VZV disease. We review the vaccines' efficacy, safety, effectiveness and coverage using evidence from trials, observational studies from large routine health datasets and clinical post-marketing surveillance studies and outline newer developments in subunit and inactivated vaccines. Expert commentary: Safe and effective, varicella and zoster vaccines have already made major inroads into reducing the burden of VZV disease globally. As these live vaccines have the potential to reactivate and cause clinical disease, developing alternatives that do not establish latency is an attractive prospect but will require better understanding of latency mechanisms.

A systematic review of varicella seroprevalence in European countries before universal childhood immunization: deriving incidence from seroprevalence data

Surveillance systems for varicella in Europe are highly heterogeneous or completely absent. We estimated the varicella incidence based on seroprevalence data, as these data are largely available and not biased by under-reporting or underascertainment. We conducted a systematic literature search for varicella serological data in Europe prior to introduction of universal varicella immunization. Age-specific serological data were pooled by country and serological profiles estimated using the catalytic model with piecewise constant force of infection. From the estimated profiles, we derived the annual incidence of varicella infection (/100·000) for six age groups (<5, 5–9, 10–14, 15–19, 20–39 and 40–65 years). In total, 43 studies from 16 countries were identified. By the age of 15 years, over 90% of the population has been infected by varicella in all countries except for Greece (86·6%) and Italy (85·3%). Substantial variability across countries exists in the age-specific annual incidence of varicella primary infection among the <5 years old (from 7052 to 16 122 per 100 000) and 5–9 years old (from 3292 to 11 798 per 100 000). The apparent validity and robustness of our estimates highlight the importance of serological data for the characterization of varicella epidemiology, even in the absence of sampling or assay standardization.