Hospitalizations for varicella in children and adolescents in a referral hospital in Hong Kong, 2004 to 2008: a time series study

Economic burden of varicella in Bangkok, Thailand: A multicenter medical chart review study

Our multicenter, medical chart review, cost-of-illness study used a micro-costing approach to evaluate the economic burden associated with varicella in Bangkok, Thailand, from a societal perspective. We reviewed medical charts of adults and children with a primary diagnosis of varicella (2014-2018) from 4 hospitals in Bangkok. Reported healthcare resource utilization and missed school or workdays were extracted from medical charts. Mean direct, indirect, and total costs per patient were estimated for overall, adult, and pediatric patients (2020 USD). Of the 200 children and 60 adults, 99.6%, 5.4%, and 5.4% had a varicella-related outpatient visit, emergency department visit, and hospitalization, respectively. The mean direct medical cost was 33 USD for pediatric and adult patients. The mean cost of outpatient visits (8 vs 13 USD, P<0.001) and medications (7 vs 9 USD, P<0.001) was significantly lower among pediatric patients. Forty-eight children reported a mean of 5.8 school days lost, and 32 adult patients reported a mean of 7.4 workdays lost. The mean total cost per varicella patient was 89 USD, with the mean total cost higher for adult than pediatric patients (145 vs 72 USD, P<0.001). Indirect cost accounted for 63% of the total cost per patient (54% for pediatric patients and 77% for adult patients). There is a substantial economic burden associated with patients seeking varicella-related healthcare in Thailand, including considerable indirect costs.

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.

Chickenpox outbreak among Venezuelan immigrants housed in shelters and occupancies in the state of Roraima, Brazil, 2019: a descriptive study

OBJECTIVE

To describe chickenpox outbreak among Venezuelan immigrants in shelters and occupancies in the municipalities of Pacaraima and Boa Vista, the state capital of Roraima, Brazil, and the control measures implemented.

METHODS

This was a descriptive case series study, conducted between November 21 and December 13, 2019, based on secondary database obtained from the outbreak investigation made available by the General Coordination for the National Immunization Program. Descriptive analysis was performed using simple and relative frequency measurements, and measures of central tendency and dispersion were calculated.

RESULTS

Of the 9,591 immigrants, 38 active cases and 1,459 susceptible to varicella were identified. With regard to active cases, 23 were female, and those aged under 9 years (17 cases) were the most affected.

CONCLUSION

People susceptible to chickenpox were identified during the investigation. Immunization actions aimed at reducing transmission were adopted, thus preventing severe cases, deaths and overload in local health care system.

Study of Complications of Varicella-Zoster Virus Infection in Hospitalized Children at a Reference Hospital for Infectious Disease Treatment

OBJECTIVES

Varicella is a disease with potentially severe complications. We aimed to investigate characteristics of hospitalized children with varicella in Brazil in the prevaccine period and to identify predictors for requiring intensive care treatment.

METHODS

A prospective cohort study was conducted from May 2011 to April 2014. Patients up to 13 years of age with varicella diagnosis were included. Information was collected through interview and review of medical records. Logistic regression analysis was performed.

RESULTS

A total of 669 patients were admitted. The median age of subjects was 2.7 years (range 0-14 years) with a predominance of boys (56.6%). The main causes of hospitalization were bacterial complications (77.7%), viral complications (11.4%), and at-risk patients (10.9%). Main bacterial complications were skin infection and pneumonia. Main viral complications were herpes zoster, cerebellitis, and encephalitis. Most at-risk patients used corticosteroids or had a diagnosis of leukemia. At-risk patients were hospitalized earlier (P < .01) and remained hospitalized for longer periods (P = .03). A total of 44 patients (6.6%) were admitted to the ICU, and 5 (0.8%) died of septic shock. Thrombocytopenia was associated with more severe illness in patients with bacterial infections (P = .001). The long-time interval between onset of infection and admission was associated with the need for intensive care in all groups (P = .007).

CONCLUSIONS

Secondary bacterial infection is the main cause of hospitalization, and thrombocytopenia in these patients leads to worse outcomes. Difficulties of access to the health system and delay in medical care are determining factors of greater severity in this population.

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.

Acute Cerebellitis in Children: A Variable Clinical Entity

Acute cerebellar ataxia is the most common cause of acute ataxia in children and it usually runs a self-limiting and ultimately benign clinical course. A small proportion of children have evidence of inflammatory swelling in the cerebellum. Many of these children suffer more severe and potentially life-threatening forms of cerebellar ataxia and may need more intensive treatments including urgent neurosurgical treatments. This more severe form of acute cerebellar ataxia is often termed acute cerebellitis. Many children with acute cerebellitis have long-term neurological sequela and evidence of structural cerebellar changes on follow-up imaging. Several patterns of cerebellar inflammation have been described. The authors describe the variabilities in the clinical and radiological patterns of disease in the cases that have been described in the literature.

Role of meteorological conditions in reported chickenpox cases in Wuhan and Hong Kong, China

BACKGROUND

Chickenpox is a common contagious disease that remains an important public health issue worldwide. Over 90% of unvaccinated individuals become infected, but infection occurs at different ages in different parts of the world. Many people have been infected by 20 to 30 years of age in China, and adults and pregnant women who become infected often develop severe infection. Furthermore, a mortality rate of 2-3 per 100,000 infected persons has been reported. In this study, we explore the temperature-dependent transition of patterns of reported chickenpox cases in two large subtropical climate cities, Wuhan and Hong Kong, China, to aid in the prediction of epidemics and preparation for the effects of climatic changes on epidemiology of chickenpox in China.

METHODS

We used a time series analysis comprising a spectral analysis based on the maximum entropy method in the frequency domain and the nonlinear least squares method in the time domain. Specifically, the following time series data were analyzed: data of reported chickenpox cases and meteorological data, including the mean temperature, relative humidity and total rainfall in Wuhan and Hong Kong from January 2008 to June 2015.

RESULTS

The time series data of chickenpox for both Wuhan and Hong Kong have two peaks per year, one in winter and another in spring, indicating a bimodal cycle. To investigate the source of the bimodal cycle of the chickenpox data, we defined the contribution ratio of the 1-year cycle, Q 1, and the 6-month cycle, Q 2, as the contribution of the amplitude of a 1-year cycle and a 6-month cycle, respectively, to the entire amplitude of the time-series data. The Q 1 values of Wuhan and Hong Kong were positively correlated with the annual mean temperature and rainfall of each city. Conversely, the Q 2 values of Wuhan and Hong Kong were negatively correlated with the annual mean temperature and rainfall of Wuhan and Hong Kong.

CONCLUSION

Our results showed that the mean temperature and rainfall have a significant influence on the incidence of chickenpox, and might be important predictors of chickenpox incidence in Wuhan and Hong Kong.

Seroprevalence and Risk Factors of Varicella Zoster Infection in Iranian Adolescents: A Multilevel Analysis; The CASPIAN-III Study

The objective of this study was to evaluate the varicella zoster virus (VZV) immunity in Iranian adolescents. It was conducted as a primary study for vaccine implementation, and to investigate the association of climatic and socioeconomic factors with the epidemiology of this infection. In this cross- sectional study, anti VZV antibodies were measured in serum samples obtained in a national school-based health survey (CASPIAN- III). Association of demographic, socio-economic, and climate of the living region with the frequency of VZV was investigated by multivariate multilevel analysis. Overall, sera of 2753 individuals aged 10–18 were tested for VZV antibodies, from those 87.4% were positive. The prevalence was statistically different in four socio-geographic regions (P<0.001), varying between 85.24% in West region (mostly mountainous areas with cold climate) to 94.59% in Southeast region (subtropical climate). Among variables studied, only age and mean daily temperature of the living area were positively associated with the VZV seroprevalence. Our findings show that most Iranians develop immunity to VZV before the age of 10, but a substantial proportion of them are yet susceptible to the infection. Therefore, it seems that the best strategy to reduce the burden of the disease is to vaccinate high- risk adults, i.e. those without a history of varicella infection. The regional temperature might be the only determinant of VZV epidemiology in Iran.

Varicella Skin Complications in Childhood: A Case Series and a Systematic Review of the Literature

Even if varicella is generally considered a harmless disease in childhood, severe complications may occur. We examined varicella skin complications (VSCs) in hospitalized immunologically healthy children, over a nine-year period. We also systematically analyzed previous reports to calculate the rate of VSCs in the literature. VSCs occurred in 16.4% of children hospitalized for varicella. This figure is in accordance with the literature, as the range of VSCs was 2.6%-41.2%. Skin complications may represent determinants of hospitalization and of other indirect costs in young children.

Association between the incidence of varicella and meteorological conditions in Jinan, Eastern China, 2012-2014

BACKGROUND

Varicella remains an important public health issue in China. In this study we explored the effect of weather conditions on the incidence of varicella in the temperate city of Jinan, Eastern China during 2012-2014 to inform public health prevention and control measures.

METHODS

Data on reported cases of varicella were obtained from National Notifiable Disease Report System. Meteorological data for the same time period were obtained from the Jinan Meteorological Bureau. A negative binomial regression model was used to assess the relationships between meteorological variables and the incidence of varicella. Given collinearity between average temperature and atmospheric pressure, separate models were constructed: one including average temperature without atmospheric pressure, the other including atmospheric pressure but without average temperature. Both models included relative humidity, wind velocity, rainfall, sunshine, and year as independent variables.

RESULTS

Annual incidence rates of varicella were 44.47, 53.69, and 46.81 per 100,000 for 2012, 2013, and 2014, respectively. Each increase of 100 Pa (hPa) in atmospheric pressure was estimated to be associated with an increase in weekly incidence of 3.35 % (95 % CI = 2.94-3.67 %), while a 1 °C rise in temperature was associated with a decrease of 3.44 % (95 % CI = -3.73-3.15 %) in the weekly incidence of varicella. Similarly, a 1 % rise in relative humidity corresponded to a decrease of 0.50 % or 1.00 %, a 1 h rise in sunshine corresponded to an increase of 1.10 % or 0.50 %, and a 1 mm rise in rainfall corresponded to an increase of 0.20 % or 0.30 %, in the weekly incidence of varicella cases, depending on the variable considered in the model.

CONCLUSION

Our findings show that weather factors have a significant influence on the incidence of varicella. Meteorological conditions should be considered as important predictors of varicella incidence in Jinan, Eastern China.

Parental Attitudes and Factors Associated With Varicella Vaccination in Preschool and Schoolchildren in Hong Kong: A Cross-Sectional Study

This study investigates parental attitudes and factors associated with varicella vaccination among preschool and schoolchildren prior to introduction of the vaccine into Hong Kong's universal Childhood Immunization Program.Fourteen kindergartens and 5 primary schools in Hong Kong were randomly selected in 2013. Parents of the students were invited to answer the self-administered questionnaires. Acquired information included demographic characteristics and socioeconomic statuses of families, children's history of chickenpox infection and vaccination, and reasons for getting children vaccinated. Logistic regression was applied to examine the factors associated with vaccination.From the 3484 completed questionnaires, the calculated rates of varicella infection and vaccination were 20.7% and 69.0%, respectively. Barriers to vaccination included parental uncertainties about vaccine effectiveness, lack of recommendation from the government, and concerns on adverse effects. Overall, 71.8%, 69.0%, and 45.7% of the parents rated family doctors, specialists, and the government, respectively, as very important motivators of vaccination. Higher parental educational level and family income, better perceived knowledge of varicella and chance of infection, discussion with a family doctor, and positive health belief towards vaccination were associated with vaccination (all P < 0.05).The rate of vaccination in Hong Kong was higher than that of some other countries that also did not include the vaccine in their routine immunization programs. More positive parental attitudes, higher socioeconomic status, and discussion with a family doctor are associated with greater vaccination rates. The important roles that health professionals and the government play in promoting varicella vaccination were emphasized.

The potential impact of climate change and ultraviolet radiation on vaccine-preventable infectious diseases and immunization service delivery system

Climate change and solar ultraviolet radiation may affect vaccine-preventable infectious diseases (VPID), the human immune response process and the immunization service delivery system. We systematically reviewed the scientific literature and identified 37 relevant publications. Our study shows that climate variability and ultraviolet radiation may potentially affect VPID and the immunization delivery system through modulating vector reproduction and vaccination effectiveness, possibly influencing human immune response systems to the vaccination, and disturbing immunization service delivery. Further research is needed to determine these affects on climate-sensitive VPID and on human immune response to common vaccines. Such research will facilitate the development and delivery of optimal vaccination programs for target populations, to meet the goal of disease control and elimination.

Sero-Prevalence of Antibodies against Varicella Zoster Virus in Children under Seven-Years Old in 2012 in Tehran, Iran

BACKGROUND

Varicella zoster virus (VZV) is a member of herpes family viruses, which causes varicella (chickenpox) after primary infection and herpes zoster (shingles) because of latent virus reactivation from dorsal root ganglia. Generally, prevalence of varicella antibodies increases with age. We aimed to compare the prevalence of anti-VZV antibody in children under seven years old, in order to obtain a preliminarily picture of general presence of these antibodies to design an immunization plan.

METHODS

In this cross-sectional study, performed from September 2011 to September 2012 in Tehran, Iran, 267 serum samples including sera from 7 month old infants, n= 87; 18 month old children, n= 86; and 6 year old children, n= 94 were assessed for the presence of specific IgG antibodies against VZV, using ELISA technique.

RESULTS

4.6% of 7 month, 12.8% of 18 month and 21.3% of 6-year-old children were seropositive. No relation was found between demographic variables (e.g. age and birth weight) and seropositivity in these age groups. VZV antibodies increased with age. Serum levels of varicella antibodies were elevated in 18 months old compared to 7 months old children, significantly (P < 0.001).

CONCLUSION

In view of the significant elevation of VZV antibodies in children from 7 months to 18 months of age and rate of seronegative children, our results support the necessity of varicella immunization between 7 and 18 months of age in order to prevent viral infection.

Meteorological factors and El Nino Southern Oscillation are associated with paediatric varicella infections in Hong Kong, 2004-2010

Varicella accounts for substantial morbidities and remains a public health issue worldwide, especially in children. Little is known about the effect of meteorological variables on varicella infection risk for children. This study described the epidemiology of paediatric varicella notifications in Hong Kong from 2004 to 2010, and explored the association between paediatric varicella notifications in children aged <18 years and various meteorological factors using a time-stratified case-crossover model, with adjustment of potential confounding factors. The analysis found that daily mean temperature, atmospheric pressure and Southern Oscillation Index (SOI) were positively associated with paediatric varicella notifications. We found that an interquartile range (IQR) increase in temperature (8·38°C) at lag 1 day, a 9·50 hPa increase in atmospheric pressure for the current day, and a 21·91 unit increase in SOI for the current day may lead to an increase in daily cases of 5·19% [95% confidence interval (CI) 1·90-8·58], 5·77% (95% CI 3·01-8·61), and 4·32% (95% CI 2·98-5·68), respectively. An IQR increase in daily relative humidity (by 11·96%) was associated with a decrease in daily paediatric varicella (-2·79%, 95% CI -3·84 to -1·73). These findings suggest that meteorological factors might be important predictors of paediatric varicella infection in Hong Kong.

Acute cerebellitis in varicella: a ten year case series and systematic review of the literature

Background

Acute cerebellitis (AC) is the most common neurological complication of varicella. Nevertheless, it has been scarcely studied. The objective of this study were to asses the occurrence of AC among children hospitalized for varicella and to analyze its specific clinical picture and outcome.

Methods

We retrospectively reviewed the medical records of children admitted to the hospital for varicella between 1^st October 2003 and 1^st June 2013 and we compared our results with literature. Children were all unvaccinated for varicella.

Results

In our case series, AC was found out in 48 out of 457 patients (10.5%). The highest frequency of AC was observed in children from 1 to 5 years of age (60.9%). The most characteristic symptom of AC was a broad-based gait disturbance that progressed gradually over the course of a few days (95.8%). Other common symptoms included slurred speech (37.5%), vomiting (31.25%), headache (29.16%), dysmetry (25%) and tremor (22.91%). After a long hospitalization (median of 11 days), all but one children were dismissed without invalidating sequelae.

Conclusions

Data from this study may help to better address the problem of varicella cerebellar complications in hospitalized children and to monitor changes over time caused by an increase in vaccination coverage.

Dysregulated microRNA expression in serum of non-vaccinated children with varicella

Circulating microRNAs (miRNAs) may play an important role in pathogen-host interactions and can serve as molecular markers for the detection of infectious diseases. To date, the relationship between circulating miRNAs and varicella-zoster virus (VZV) caused varicella has not been reported. Using TaqMan Low-Density Array (TLDA) analysis, expression levels of miRNAs in serum samples from 29 patients with varicella and 60 patients with Bordetella pertussis (BP), measles virus (MEV) and enterovirus (EV) were analyzed. The array results showed that 247 miRNAs were differentially expressed in sera of the varicella patients compared with healthy controls (215 up-regulated and 32 down-regulated). Through the following qRT-PCR confirmation and receiver operational characteristic (ROC) curve analysis, five miRNAs (miR-197, miR-629, miR-363, miR-132 and miR-122) were shown to distinguish varicella patients from healthy controls and other microbial infections with moderate sensitivity and specificity. A number of significantly enriched pathways regulated by these circulating miRNAs were predicted, and some of them were involved in inflammatory response, nervous system and respiratory system development. Our results, for the first time, revealed that a number of miRNAs were differentially expressed during VZV infection, and these five serum miRNAs have great potential to serve as biomarkers for the diagnosis of VZV infection in varicella patients.

Time trends in pediatric hospitalizations for varicella infection are associated with climatic changes: a 22-year retrospective study in a tertiary Greek referral center

BACKGROUND/AIMS

The transmission rate of air-borne infectious diseases may vary secondary to climate conditions. The study assessed time trends in the seasonality of hospitalized varicella cases in a temperate region in relation to climatic parameters prior to the implementation of universal varicella immunization.

METHODS

A retrospective descriptive study was conducted among all pediatric and adolescent varicella patients (n = 2366) hospitalized at the "Aghia Sophia" Children's Hospital during 1982-2003 in Athens, Greece. Date of infection was computed based on hospital admission date. Seasonal and monthly trends in the epidemiology of varicella infection were assessed with time series analysis (ARIMA modeling procedure). The correlation between the frequency of varicella patients and the meteorological parameters was examined by the application of Generalized Linear Models with Gamma distribution.

RESULTS

During 1982-2003, the occurrence of hospitalized varicella cases increased during summer (p = 0.025) and decreased during autumn (p = 0.021), and particularly in September (p = 0.003). The frequency of hospitalized varicella cases was inversely associated with air temperature (p<0.001). In contrast, the occurrence of hospitalized varicella cases was positively associated with wind speed (p = 0.009).

CONCLUSIONS

Pediatric hospitalizations for varicella infection rates have increased during summer and decreased during autumn in the examined temperate region. Time trends in hospitalized varicella cases are associated with climatic variables.