Varicella Vaccination Coverage Research Articles

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.

Low vaccine coverage and varicella outbreaks in Brazil − 2019-2022

The persistence of varicella outbreaks in Brazil has underscored the high concern with the low vaccine coverage in the last 4 years.Using publicly available data from the Brazilian Health System (SUS), this study analyzed varicella vaccine coverage and incidence trends from 2019 to 2022 in Brazilian States. Vaccine coverage decreased nationally in 2020, possibly influenced by the COVID-19 pandemic’s initial phase.In Bahia State, we have the persistence of varicella with an incidence rate of 3.0 cases per 100,000 inhabitants (higher incidence compared to other States) in 2023. Under 15 months children and young children (4–6 Years old) faced the highest risk, urging the importance of vaccination. Despite a monovalent varicella vaccine being available through Brazil’s National Immunization Program (NIP), Bahia fell short of achieving the ≥95 % disease control target for coverage.The study highlight the importance of vaccines to prevent some infectious diseases, as varicella, in poor tropical regions. Addressing vaccine hesitancy and misinformation, and augmenting awareness campaigns, are important to achieve and sustain high vaccine coverage over 80% as WHO guidelines to obtain a safe rate of protection for Brazilian population (Brazil's national immunization program has a target of 95% coverage).

The epidemiology of varicella and effectiveness of varicella vaccine in Ganyu, China: a long-term community surveillance study

BackgroundThe real-world data of long-term protection under moderate vaccination coverage is limited. This study aimed to evaluate varicella epidemiology and the long-term effectiveness under moderate coverage levels in Ganyu District, Lianyungang City, Jiangsu Province.MethodsThis was a population-based, retrospective birth cohort study based on the immunization information system (IIS) and the National Notifiable Disease Surveillance System (NNDSS) in Ganyu District. Varicella cases reported from 2009 to 2020 were included to describe the epidemiology of varicella, and eleven-year consecutive birth cohorts (2008–2018) were included to estimate the vaccine effectiveness (VE) of varicella by Cox regression analysis.ResultsA total of 155,232 native children and 3,251 varicella cases were included. The vaccination coverage was moderate with 37.1%, correspondingly, the annual incidence of varicella infection increased 4.4-fold from 2009 to 2020. A shift of the varicella cases to older age groups was observed, with the peak proportion of cases shifting from 5–6 year-old to 7–8 year-old. The adjusted effectiveness of one dose of vaccine waned over time, and the adjusted VE decreased from 72.9% to 41.8% in the one-dose group.ConclusionsThe insufficient vaccination coverage (37.1%) may have contributed in part to the rising annual incidence of varicella infection, and a shift of varicella cases to older age groups occurred. The effectiveness of one dose of varicella vaccine was moderate and waned over time. It is urgent to increase varicella vaccine coverage to 80% to reduce the incidence of varicella and prevent any potential shift in the age at infection in China.

Australian Paediatric Surveillance Unit (APSU) Annual Surveillance Report 2022.

For 30 years the Australian Paediatric Surveillance Unit (APSU) has conducted national surveillance of rare communicable diseases and rare complications of communicable diseases. In this report, we describe the results of thirteen such studies surveyed by the APSU in 2022, including reported case numbers and incidence estimates, demographics, clinical features, management and short-term outcomes. Conditions described are: acute flaccid paralysis (AFP); congenital cytomegalovirus (cCMV); neonatal and infant herpes simplex virus (HSV) infection; perinatal exposure to human immunodeficiency virus (HIV) and paediatric HIV infection; severe complications of influenza; juvenile-onset recurrent respiratory papillomatosis (JoRRP); congenital rubella infection/syndrome; congenital varicella syndrome (CVS) and neonatal varicella infection (NVI); and the new conditions dengue; Q fever; and severe acute hepatitis. In 2022, cases of severe complications of influenza were reported to the APSU for the first time since 2019. This likely reflects the easing of government-mandated restrictions imposed in 2020-2021 to curb the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the re-emergence of a range of infectious diseases. As previously, AFP surveillance by the APSU contributed to Australia achieving a minimum target incidence of one AFP case per 105 children aged less than 15 years. Cases of JoRRP and NVI were reported in 2022. This indicates potential gaps in human papillomavirus (HPV) and varicella vaccination coverage respectively, especially in high-risk groups such as young migrant and refugee women of childbearing age from countries without universal vaccination programs. Paediatric HIV case numbers resulting from mother-to-child-transmission (MTCT) of HIV remain low in Australia due to use of effective intervention strategies. However, there has been an increase in the number of imported cases of HIV in children (mainly perinatally-acquired) from countries with a high HIV prevalence. Without effective vaccines, there has been no decline in the incidence of congenital CMV and neonatal HSV, indicating the importance of early identification and management to reduce morbidity and mortality. The first cases of dengue, Q fever and severe acute hepatitis were received by APSU in 2022, including two cases of acute hepatitis in which aetiology has not been confirmed to date. The APSU has an important ongoing role in monitoring rare childhood infections.

Spatial behavior of hepatitis A, MMR, and varicella vaccination coverage in the state of Minas Gerais, 2020.

To analyze the spatial behavior of hepatitis A, measles, mumps, and rubella (MMR), and varicella vaccination coverage in children and its relationship with socioeconomic determinants in the state of Minas Gerais. This ecological study investigated records of doses administered to children, extracted from the Immunization Information System of 853 municipalities in Minas Gerais, in 2020. We analyzed the vaccination coverage and socioeconomic factors. Spatial scan statistics were used to identify spatial clusters and measure the relative risk based on the vaccination coverage indicator and the Bivariate Moran Index, and thus detect socioeconomic factors correlated with the spatial distribution of vaccination. We used the cartographic base of the state and its municipalities and the ArcGIS and SPSS software programs. Hepatitis A (89.0%), MMR (75.7%), and varicella (89.0%) showed low vaccination coverage. All vaccines analyzed had significant clusters. The clusters most likely to vaccinate their population were mainly located in the Central, Midwest, South Central, and Northwest regions, while the least likely were in the North, Northeast, and Triângulo do Sul regions. The municipal human development index, urbanization rate, and gross domestic product were spatially dependent on vaccination coverage. The spatial behavior of hepatitis A, MMR, and varicella vaccination coverage is heterogeneous and associated with socioeconomic factors. We emphasize that vaccination records require attention and should be continuously monitored to improve the quality of information used in services and research.

Spatial behavior of hepatitis A, MMR, and varicella vaccination coverage in the state of Minas Gerais, 2020

RESUMO Objetivo: Analisar o comportamento espacial da cobertura vacinal da hepatite A, tríplice viral e varicela em crianças e a relação com determinantes socioeconômicos, no estado de Minas Gerais. Métodos: Estudo ecológico que considerou os registros de doses aplicadas em crianças extraídos do Sistema de Informação de Imunização de 853 municípios mineiros, em 2020. Analisaram-se as coberturas vacinais e os fatores socioeconômicos. A estatística scan espacial foi utilizada para identificar agrupamentos espaciais e medir o risco relativo pelo indicador de cobertura vacinal e o Índice de Moran Bivariado para identificar os fatores socioeconômicos correlacionados com a distribuição espacial da vacinação. Utilizou-se a base cartográfica do estado e de seus municípios e os softwares ArcGIS e SPSS. Resultados: Observaram-se baixas coberturas para as vacinas de hepatite A (89,0%), tríplice viral (75,7%) e varicela (89,0%). Foram identificados aglomerados significativos em todas as vacinas analisadas. Os aglomerados de maior chance de a população ser vacinada se alocaram majoritariamente nas regiões Centro, Centro-Oeste, Centro-Sul, Noroeste, e as de menor propensão para a vacinação encontram-se nas regiões Norte, Nordeste e Triângulo do Sul. O índice de desenvolvimento humano municipal, a taxa de urbanização e o produto interno bruto tiveram dependência espacial com a cobertura vacinal. Conclusões: Há heterogeneidades no comportamento espacial das coberturas para as vacinas hepatite A, tríplice viral e varicela, e essa condição se encontra associada a fatores socioeconômicos. Destaca-se que os registros de vacinação requerem atenção e devem ser continuamente acompanhados para aprimoramento da qualidade das informações utilizadas nos serviços e nas pesquisas.

Celebrating 25 Years of Varicella Vaccination Coverage for Children and Adolescents in the United States: A Success Story.

Tracking vaccination coverage is a critical component of monitoring a vaccine program. Three different surveillance systems were used to examine trends in varicella vaccination coverage during the United States vaccination program: National Immunization Survey-Child, National Immunization Survey-Teen, and immunization information systems (IISs). The relationship of these trends to school requirements and disease decline was also examined. Among children aged 19-35 months, ≥1 dose of varicella vaccine increased from 16.0% in 1996 to 89.2% by the end of the 1-dose program in 2006, stabilizing around at least 90.0% thereafter. The uptake of the second dose was rapid after the 2007 recommendation. Two-dose coverage among children aged 7 years at 6 high-performing IIS sites increased from 2.6%-5.5% in 2006 to 86.0%-100.0% in 2020. Among adolescents aged 13-17 years, ≥2-dose coverage increased from 4.1% in 2006 to 91.9% in 2020. The proportion of adolescents with history of varicella disease declined from 69.9% in 2006 to 8.4% in 2020. In 2006, 92% of states and the District of Columbia (DC) had 1-dose daycare or school entry requirements; 88% of states and DC had 2-dose school entry requirements in the 2020-2021 school year. The successes in attaining and maintaining high vaccine coverage were paramount in the dramatic reduction of the varicella burden in the United States over the 25 years of the vaccination program, but opportunities remain to further increase coverage and decrease varicella morbidity and mortality.

Epidemiological Characteristics of Varicella under Different Immunisation Strategies in Suzhou Prefecture, Jiangsu Province.

Background: The varicella vaccine is excluded from the Chinese national immunisation programme but is included in the local expanded programme on immunisation (EPI) in the Suzhou Prefecture. This study investigated the epidemiological characteristics of the varicella cases during the implementation of different immunisation strategies in the Suzhou Prefecture, Jiangsu Province. Methods: In this study, we used descriptive statistics. Information on reported instances from 2012 to 2021 was first retrieved. Data on varicella cases were collected from the China Information System for Disease Control and Prevention (CISDCP). Similarly, information on vaccinated children was obtained from the Jiangsu Province Vaccination Integrated Service Management Information System (JPVISMIS). The census data in this study was procured from the Suzhou Bureau of Statistics. Results: From 2012 to 2021, a total of 118,031 cases of varicella were reported in Suzhou, and the average annual reported incidence was 91.35 per 100,000. The average yearly incidence after implementing the two-dose varicella vaccination decreased by 41.57% compared with the implementation of one dose. This study demonstrates two annual incidence peaks, a small peak between April and July and a prominent peak between October and January. It is also possible that this seasonal distribution is related to the geography of Suzhou. The average annual reported incidence between districts with a statistically significant difference (χ2 = 98.077, p < 0.05). The one-dose varicella vaccination coverage gradually increased from 55.34% in 2012 to 89.06% in 2021 and the two-dose varicella vaccination coverage gradually increased from 0.27% in 2012 to 82.17% in 2021. Conclusions: Administering the varicella vaccine in the local EPI has significantly decreased the incidence rate and the total number of cases. A two-dose vaccination schedule is still the best vaccination strategy for varicella vaccine effectiveness.

Exposure-response relationship between temperature, relative humidity, and varicella: a multicity study in South China.

Varicella is a rising public health issue. Several studies have tried to quantify the relationships between meteorological factors and varicella incidence but with inconsistent results. We aim to investigate the impact of temperature and relative humidity on varicella, and to further explore the effect modification of these relationships. In this study, the data of varicella and meteorological factors from 2011 to 2019 in 21 cities of Guangdong Province, China were collected. Distributed lag nonlinear models (DLNM) were constructed to explore the relationship between meteorological factors (temperature and relative humidity) and varicella in each city, controlling in school terms, holidays, seasonality, long-term trends, and day of week. Multivariate meta-analysis was applied to pool the city-specific estimations. And the meta-regression was used to explore the effect modification for the spatial heterogeneity of city-specific meteorological factors and social factors (such as disposable income per capita, vaccination coverage, and so on) on varicella. The results indicated that the relationship between temperature and varicella in 21 cities appeared nonlinear with an inverted S-shaped. The relative risk peaked at 20.8 ℃ (RR = 1.42, 95% CI: 1.22, 1.65). The relative humidity-varicella relationship was approximately L-shaped, with a peaking risk at 69.5% relative humidity (RR = 1.25, 95% CI: 1.04, 1.50). The spatial heterogeneity of temperature-varicella relationships may be caused by income or varicella vaccination coverage. And varicella vaccination coverage may contribute to the spatial heterogeneity of the relative humidity-varicella relationship. The findings can help us deepen the understanding of the meteorological factors-varicella association and provide evidence for developing prevention strategy for varicella epidemic.

Vaccine Coverage and Effectiveness in a School-Based Varicella Outbreak in Jinan Prefecture, Shandong Province.

Background: Licheng District of Jinan Prefecture reported a school-based varicella outbreak. We conducted an investigation to analyze the epidemiology and scope of the outbreak, determine varicella vaccine coverage on the school campus, and estimate varicella vaccine effectiveness (VE). Methods: In the epidemiological investigation, we determined the attack rate, the clinical manifestations of varicella cases, and histories of prior varicella disease and varicella vaccination. We tested students for presence of serum IgM antibodies, and we attempted to isolate the varicella virus from vesicular fluid samples. We used chi-square to compare incidences between classes and floors. VE was estimated using a retrospective cohort study. Results: There were 13 varicella cases in the outbreak. All were among fourth grade students - twelve in Class 7 and one in Class 6. The attack rate in the two classrooms was 14.3% (13/91). Clinical symptoms were rash (100%) and fever (46.15%). All cases were reported within one average incubation period, and the epidemic curve suggested common exposure. Six of the 13 cases previously received one dose of varicella vaccine with a median time between vaccination and infection of 9 years; the other seven cases had not been vaccinated. Varicella vaccine coverage with one or more doses was 81.31%; 2-dose coverage was 38.15%. The median age of receipt of dose 1 was 1.18 years, and median age for receiving dose 2 was 5.12 years. One-dose varicella VE was 73.2% (95% confidence interval: 37.0%, 88.6%), and two-dose VE was 100%. Conclusions: Varicella vaccine coverage has been gradually increasing in recent years, as ≥1-dose and 2-dose coverage rates are higher in younger children than older children. High one-dose vaccination coverage limited the outbreak scope and led to the breakthrough cases being mild. Mild cases were difficult to detect in a timely manner. Varicella vaccine was highly effective, with 1-dose VE of 73% nine years after vaccination and 2-dose VE of 100%. We strongly recommended that all school students receive two doses of varicella vaccine.

Recognition & management of varicella infections and accuracy of antimicrobial recommendations: Case vignettes study in the US.

In 1995, the CDC recommended one-dose routine varicella immunization for children <12 years of age, expanding its recommendation to two doses in 2006. Today, with widespread varicella vaccination coverage, an estimated 3.5 million cases of varicella, 9,000 hospitalizations, and 100 deaths are prevented annually in the United States. Since varicella infections are now uncommon, health care providers (HCPs) may not recognize varicella infections and may prescribe inappropriate treatment. An online survey of HCPs was conducted to assess recognition and management of varicella infections. Responses to eight varicella vignettes describing patients with varying varicella symptoms were analyzed and descriptive analyses performed. Stratified analysis comparing responses of those licensed before and in/after 1996 was also performed. 153 HCPs (50 nurse practitioners, 103 doctors) completed the survey. Mean age of respondents was 44 years. 62% were female, and 82% were licensed before 1996. Varicella infection was correctly diagnosed 79% of the time. HCPs correctly recognized uncomplicated varicella vignettes 85% of the time versus 61% of the time for complicated varicella vignettes. Antibiotics were recommended 17% of the time and antivirals 18% of the time, of which 25% and 69% (respectively) were not appropriate per guidelines. HCPs licensed before 1996 were better able to recognize varicella compared to those licensed later, but prescribed more antimicrobials medications to treat varicella. Although most HCPs recognized varicella infection, a sizable proportion could not recognize cases with complications, and some of the varicella cases were inappropriately treated with antibiotics and/or antivirals. Additional HCP training and high vaccination coverage are important strategies to avoid inaccurate diagnoses and minimize unnecessary exposure to antimicrobial/antiviral therapies.

Postinfectious Acute Cerebellar Syndromes in Children: A Nationally Ascertained Case Series From Australia 2013-2018.

Postinfectious acute cerebellar syndromes show a wide spectrum of acute severity and can occur with acute febrile illness or vaccine receipt. Varicella has historically been the most common cause, associated with up to 25% of cases in large cohorts. This study aimed to describe the spectrum of syndromes in a setting with high varicella vaccine coverage. Data were collected on children initially identified as "suspected encephalitis" subsequently designated "not-encephalitis" at participating children's hospitals in the Paediatric Active Enhanced Disease Surveillance (PAEDS) network, Australia, as part of the Acute Childhood Encephalitis study. A comprehensive descriptive analysis was undertaken on prospectively identified, national series of children with postinfectious acute cerebellar syndromes from 2013 to 2018. Cases were classified using a previously validated severity score, and the outcome was assessed at 12 months using the Liverpool Outcome Scale score. A total of 20 cases (65% were vaccinated for varicella) were included, of which 70% were subcategorized as acute cerebellar ataxia (ACA), 20% acute cerebellitis (AC), and 10% acute fulminant cerebellitis (AFC). An acute febrile illness was noted in 55% and none were related to varicella or were temporally related to varicella vaccination or other childhood vaccines. A subset (total of 7 children) followed up at 12 months all showed reduced Liverpool Outcome Scale scores. The study provides an overall description of this uncommon spectrum of neurologic syndromes and shows the infrequency of varicella zoster virus as a cause in a vaccinated population.

Reconstructing the transmission dynamics of varicella in Japan: an elevation of age at infection.

BackgroundIn Japan, routine two-dose immunization against varicella has been conducted among children at ages of 12 and 36 months since 2014, and the vaccination coverage has reached around 90%. To understand the impact of routine varicella vaccination, we reconstructed the epidemiological dynamics of varicella in Japan.MethodsEpidemiological and demographic datasets over the past three decades were analyzed to reconstruct the number of susceptible individuals by age and year. To estimate the annual risk of varicella infection, we fitted a balance equation model to the annual number of cases from 1990 to 2019. Using parameter estimates, we reconstructed varicella dynamics starting from 1990 and modeled future dynamics until 2033.ResultsOverall varicella incidence declined over time and the annual risk of infection among children younger than 10 years old decreased monotonically starting in 2014. Conversely, varicella incidence among teenagers (age 10 to 14 years) has increased each year since 2014. A substantial number of unvaccinated individuals born before the routine immunization era remained susceptible and aged without contracting varicella, while the annual risk of infection among teenagers aged 10 to 14 years increased starting in 2011 despite gradual expansion of varicella vaccine coverage. The number of susceptible individuals decreased over time in all age groups. Modeling indicated that susceptibility rates among pre-school children aged 1 to 4 years will remain low.ConclusionRoutine varicella vaccination has successfully reduced infections in pre-school and early primary school age children, but has also resulted in increased infection rates among adolescents. This temporary increase was caused both by the increased age of susceptible individuals and increased transmission risk among adolescents resulting from the dynamic nature of varicella transmission. Monitoring susceptibility among adolescents will be important to prevent outbreaks over the next decade.

Burden of comorbid conditions in children and young people with juvenile idiopathic arthritis: a collaborative analysis of 3 JIA registries.

ObjectivesBurden of comorbidities are largely unknown in JIA. From 2000, national and international patient registries were established to monitor biologic treatment, disease activity and adverse events in patients with JIA. The aim of this analysis was to investigate in parallel, for the first time, three of the largest JIA registries in Europe/internationally—UK JIA Biologic Registers (BCRD/BSPAR-ETN), German biologic registers (BiKeR/JuMBO), multinational Pharmachild—to quantify the occurrence of selected comorbidities in patients with JIA.MethodsInformation on which data the registers collect were compared. Patient characteristics and levels of comorbidity were presented, focussing on four key conditions: uveitis, MAS, varicella, and history of tuberculosis. Incidence rates of these on MTX/biologic therapy were determined.Results8066 patients were registered into the three JIA registers with similar history of the four comorbidities across the studies; however, varicella vaccination coverage was higher in Germany (56%) vs UK/Pharmachild (16%/13%). At final follow-up, prevalence of varicella infection was lower in Germany (15%) vs UK/Pharmachild (37%/50%). Prevalence of TB (0.1–1.8%) and uveitis (15–19%) was similar across all registers. The proportion of systemic-JIA patients who ever had MAS was lower in Germany (6%) vs UK (15%) and Pharmachild (17%).ConclusionThis analysis is the first and largest to investigate the occurrence of four important comorbidities in three JIA registries in Europe and the role of anti-rheumatic drugs. Combined, these three registries represent one of the biggest collection of cases of JIA worldwide and offer a unique setting for future JIA outcome studies.

A randomized trial assessing the efficacy, immunogenicity, and safety of vaccination with live attenuated varicella zoster virus-containing vaccines: ten-year follow-up in Russian children

ABSTRACT In Russia, a universal varicella vaccination (UVV) program has not been implemented, and varicella vaccination coverage is low. We assessed the efficacy, antibody persistence, and safety of one- and two-dose varicella vaccination schedules in Russian children with a ten-year follow-up period, as part of an international phase IIIB, observer-blind, randomized, controlled trial (NCT00226499). Children aged 12–22 months were randomized (3:3:1) to receive two doses of tetravalent measles-mumps-rubella-varicella vaccine (V2 group), one dose trivalent measles-mumps-rubella (MMR) vaccine and one dose of varicella vaccine (V1 group), or two doses of MMR vaccine (V0 [control] group), 42 days apart. Main study outcomes were: vaccine efficacy (VE) against confirmed varicella cases, anti-varicella zoster virus (VZV) seropositivity rates and geometric mean concentrations, and reporting of (serious) adverse events ([S]AEs). The total vaccinated cohort in Russia comprised 1000 children; 900 were followed up until study end (year [Y] 10). VE estimates against confirmed varicella (Y10) were 92.4% in the V2 group and 74.7% in the V1 group. Anti-VZV seropositivity rates remained ≥99.4% in the V2 group and ≥89.7% in the V1 group from day 42 post-vaccination 2 until Y10. Occurrence of (un)solicited AEs and SAEs was similar across groups and confirmed the safety profile of the vaccines. No vaccination-related SAEs or deaths were reported. These results are consistent with the global trial results, i.e., the highest VE estimates observed following the two-dose schedule compared to the one-dose schedule. These data may inform decision-making related to potential implementation of a UVV program.

Upgrading the school entry vaccination record check strategy to improve varicella vaccination coverage: results from a quasi-experiment study

ABSTRACT Background The school entry vaccination record check strategy (SECS) is an appropriate opportunity to recommend vaccines for students to improve vaccination coverage (VC). However, it is only utilized for providing necessary catch-up vaccination for students who are missing the Expanded Program on Immunization (EPI) vaccines in China. We aimed to address that gap and quantify the relationship between the SECS policy and the increase of coverage in varicella vaccine (VarV). Methods We employed a pretest and posttest quasi-experimental design to examine the effect of the upgraded SECS policy on the change of VarV coverage in newly enrolled students in Lu’an, 2019–2020. Results Eight hundred participants were randomly divided into the control group (C group, 31.8%), the telephone-based intervention group (T group, 31.2%), and the written notification intervention group (W group, 37.0%). Totally, 84 students received VarV during the study period, with a VC of 10.5%. The possibility of vaccination in the T group (RR = 4.9, 95% CI:2.2–10.9) and W group (RR = 5.2, 95% CI:2.4–11.5) was significantly higher than that in the C group (p< .001). Conclusions Our study demonstrates that the upgraded SECS produce a positive effect on improving the VC of VarV. This nudge strategy may decrease varicella outbreaks in schools in China, especially in provinces where VarV is not introduced into EPI.

Varicella vaccination as useful strategy for reducing the risk of varicella-related hospitalizations

Abstract Introduction The present study summarizes evidences of the impact of varicella vaccination (VV) on hospitalization rates attributable to this infectious disease in Italy. Methods We have carried out a retrospective observational study that analysed hospital discharge records and VV coverage at 24 months collected from 2003 to 2018 by the Italian Health Ministry. All hospitalizations with the presence of an ICD-9 CM 059.X code in the principal diagnosis or in any of the five secondary diagnoses were considered as related to varicella. The hospitalization rate reduction was evaluated by calculating average annual percent change (AAPC) through joint-point analysis. Results Hospitalization rates showed a decreasing risk by age: children aged &amp;lt;1 year were the most affected age group in each region (42.56/100,000 per year), whereas lower incidence rates were found in older age groups (23.76/100,000 in 1 to 5 years age group and &amp;lt;4/100,000 in the following groups). Varicella hospitalization rates decreased significantly after the introduction of VV (3.42 vs. 2.67 per 100,000; P &amp;lt; 0.001). During the first five years after vaccination introduction hospitalization rates showed a statistically significant decrease especially for infants aged &amp;lt;1 year (AAPC -34.98%; p &amp;lt; 0.001) and 1 to 5 years old (AAPC -35.22%; P &amp;lt; 0.01). VV coverage was strongly correlated with hospitalization rates decrease over each paediatric age group (R-squared 0.38 in aged &amp;lt;1 year, p &amp;lt; 0.001; 0.71 in 1 to 5 years old, p &amp;lt; 0.001; 0.93 in 6 to 14 years old, p &amp;lt; 0.0001). Conclusions All the previously reported findings confirm that hospitalization rates are strictly related to both the number of years since vaccination introduction and the vaccination coverage. VV confirms to be an important step in public health strategies and the introduction of universal vaccination, with high vaccination coverage, should be considered as an extremely powerful tool for reducing the risk of complications. Key messages This study adds update findings to the literature and shows that varicella hospitalizations in Italy, from 2003 to 2018, have reduced their burden, that was high in years before varicella vaccination. Varicella vaccination introduction and high coverage are powerful tools for reducing the risk of varicella complications and related hospitalizations in the general population.

Varicella vaccination as useful strategy for reducing the risk of varicella-related hospitalizations in both vaccinated and unvaccinated cohorts (Italy, 2003–2018)

IntroductionThe present study summarizes evidences of the impact that varicella vaccination (VV) introduction and coverage can have on varicella attributable hospitalization rates. MethodsA retrospective observational study was carried out by considering hospital discharge records and VV coverage at 24 months collected from 2003 to 2018 by the Italian Ministry of Health. All hospitalizations records reporting an ICD-9 CM 052.X code as the principal diagnosis or any of the five secondary diagnoses were considered as related to varicella. The hospitalization rate reduction was evaluated by calculating average annual percent change (AAPC) through joint-point analysis. ResultsHospitalization rates showed a decreasing trend by age: children <1 year of age were the most affected group in each Italian administrative region (42.5/100,000 per year), whereas lower incidence rates were found in older age groups (23.8/100,000 in 1–5 years old and <4.0/100,000 in the following groups). Varicella hospitalization rates decreased significantly after the introduction of VV (3.4 vs. 2.7 per 100,000; p < 0.001). During the first five years after the introduction of vaccination, hospitalization rates showed a statistically significant decrease especially among infants <1 year of age (AAPC −35.0%; p < 0.001) and 1–5 years old (AAPC −35.2%; p < 0.01). Total percentage changes were −80.0% and −86.7%, in the age class <1 year old and 1–5 years old, respectively. ConclusionsAll the previously reported findings confirm that hospitalization rates are strictly related to both the vaccination coverage and the number of years since the introduction of the vaccination. VV confirms to be an important step in public health strategies and the introduction of universal vaccination, with high vaccination coverage, should be considered as an extremely powerful tool to reduce the risk of complications.

Impact of a 2-dose voluntary vaccination strategy on varicella epidemiology in Beijing, 2011–2017

BackgroundOne-dose voluntary varicella vaccination for children was introduced in Beijing since 1998. In Oct 2012, a second dose varicella vaccine (VarV) was recommended to further decrease varicella disease and the outbreaks. We describe the impact of the 2-dose voluntary vaccination strategy on varicella epidemiology in Beijing, China. MethodsVaricella incidence rates and outbreak characteristics in 2011–2017 was examined using surveillance data. Varicella vaccination coverage among children born in 2007–2012 was estimated through Beijing children immunization registry system. Vaccine effectiveness (VE) for VarV2 was estimated by screening method. ResultsOverall varicella incidence decreased by 37.8% from 103.2 per 100,000 population in 2011 to 64.2 per 100,000 population in 2017. Incidence declines in children aged <15 years with most significantly decrease by 82.3% in children aged 5–9 years, while no significant change happened in adolescent and adults. A total of 251 outbreaks with 3239 outbreak-related cases were reported in 2011–2017, the number of outbreaks decreased significantly by 50.7% from 69 in 2011 to 34 in 2017. The VarV1 coverage ranged from 85.4% to 92.6% among children 4 year of age and the VarV2 coverage ranged from 40.1% to 72.9% among children 6 year of age in the 2007–2012 birth cohort. Overall VE estimates against all varicella disease was 94.4% (95% CI: 89.9–98.9%) for VarV2. ConclusionsModerate VarV2 coverage has been achieved in Beijing resulting in remarkable declining of the incidence in children. Varicella outbreaks has not been eliminated suggested that measures such as including a 2-dose varicella vaccination in routine immunization program should be taken in the future.

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).

BackgroundUniversal 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.MethodsChildren < 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.ResultsBetween 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%.DiscussionCorresponding 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.ConclusionWithin 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.Electronic supplementary materialThe online version of this article (10.1007/s40121-019-00273-6) contains supplementary material, which is available to authorized users.