Safety of zoster vaccine in adults from a large managed-care cohort: a Vaccine Safety Datalink study.

OBJECTIVES: The aim of this study was to examine a large cohort of adults who received the zoster vaccine for evidence of an increased risk of prespecified adverse events requiring medical attention. DESIGN: Two self-comparison approaches, including a case-centred approach and a self-controlled case series (SCCS) analysis were used. SETTING: Eight managed-care organizations participating in the Vaccine Safety Datalink project in the United States. SUBJECTS: A total of 193 083 adults aged 50 and older receiving a zoster vaccine from 1 January 2007 to 31 December 2008 were included. MAIN OUTCOME MEASURES: Prespecified adverse events were identified by aggregated International Classification of Diseases, Ninth Revision (ICD-9) codes in automated health plan datasets. RESULTS: The risk of allergic reaction was significantly increased within 1-7 days of vaccination [relative risk = 2.13, 95% confidence interval (CI): 1.87-2.40 by case-centred method and relative rate = 2.32, 95% CI: 1.85-2.91 by SCCS]. No increased risk was found for the following adverse event groupings: cerebrovascular events; cardiovascular events; meningitis; encephalitis; and encephalopathy; and Ramsay-Hunt syndrome and Bell's palsy. CONCLUSIONS: The results of this study support the findings from the prelicensure clinical trials, providing reassurance that the zoster vaccine is generally safe and well-tolerated with a small increased risk of allergic reactions in 1-7 days after vaccination.

Population-based epidemiologic study of Wilson's disease in Taiwan.

BACKGROUND: The purpose of the study is to investigate the epidemiology and medical expenses of Wilson's disease in Taiwan. METHODS: Cases of Wilson's disease were identified from the National Health Insurance Research Database with corresponding International Classification of Diseases, Ninth Revision (ICD-9) code 275.1 from January 2000 to December 2005. Age and sex-specific incidences were estimated by dividing the incidence number by population data obtained from the Department of Statistics, Ministry of the Interior. RESULTS: During the study period, 495 cases of Wilson's disease were identified. The male to female ratio was 1.28. The average annual incidence rate was 0.27 per 100,000, and the incidence rate peaked in the age group of 15-19 years. Most cases were juvenile and young adults. The prevalence increased steadily during the study period. Cirrhosis of the liver was the most common co-existing condition. CONCLUSIONS: This is the first population-based epidemiologic study of Wilson's disease in Taiwan. Because of the effective and affordable treatment, the prevalence of Wilson's disease in Taiwan is expected to increase continuously.

Analysis of factors associated with varicella-zoster virus susceptibility among children 0-12 years old in Taiwan.

OBJECTIVES: Varicella is a highly infectious disease caused by varicella-zoster virus (VZV). The aim of this study was to explore the geographical difference of VZV antibody seroprevalence among children in private vaccination areas in Taiwan, controlling for potential factors relating to varicella susceptibility. PATIENTS AND METHOD: A cross-sectional survey of the seroprevalence of VZV antibodies among children 0-12 years of age was conducted in Taiwan between August and December 2003. Sera of children visiting the outpatient unit of the participating hospitals around the island were collected. Six hundred and fifty-six parents among those of the 931 children studied agreed to answer the self-administered questionnaire regarding the possible factors associated with varicella susceptibility. IgG antibodies to VZV were measured using an enzyme-linked immunosorbent assay kit, Enzygnost anti VZV/IgG. RESULTS: The susceptibility was the highest at age 1 year, and then decreased as the age increased. Children living in southern and eastern Taiwan showed higher susceptibility to varicella than those living in northern area (odds ratio (OR) = 2.71 and 2.10, respectively). Prior history of varicella infection, varicella vaccination, and contact with cases remained to be associated with the susceptibility after multivariate analysis. CONCLUSIONS: Children who lived in tropical and rural regions and those who had no history of varicella infection, varicella vaccination, and contact with cases, might be more susceptible to varicella. Island-wide VZV seroprevalence surveillance is required to examine whether the geographical difference of susceptibility in Taiwan will become less significant or disappear after the mass varicella vaccination program initiated in 2004.

Varicella epidemiology and cost-effectiveness analysis of universal varicella vaccination program in Taiwan.

Varicella zoster virus is highly contagious and affects people worldwide. In this study, we collected local epidemiological data and evaluated the cost-effectiveness of varicella vaccination program in Taiwan. To examine the economical consequences of universal vaccination, a model of the incidence and the associated costs in a hypothetical cohort was created each year for 30 years. The incidence increased sharply after the infancy and peaked in children aged 5 years. The hospitalization rate among cases was the highest in infants, followed by adults 30 to 44 years old. The benefit-cost analysis showed that one dollar invested in the program would cost extra 46 cents in direct medical expense, but would save extra 45 cents considering the societal expenses. Substantial economical benefits can occur due to the averted unproductive days for parents. Sensitive surveillance of both varicella and zoster is essential in countries that have implemented or are about to implement varicella vaccination.

A seroepidemiology study of varicella among children aged 0-12 years in Taiwan.

The epidemiology pattern of varicella appears to vary among regions with different climates, population densities, and degrees of development. This study investigated the age-specific varicella zoster virus (VZV) seroprevalence in children aged 0 to 12 years in Taiwan and compared these seroprevalences between free and private vaccination areas. Residual sera were collected from 13 hospitals with 1,401 valid samples. Immunoglobulin G antibodies to VZV were measured by enzyme-linked immunosorbent assay. Parents of 656 children answered questions about the varicella incidence and varicella vaccination history of their children. In the 8-12 year-olds, the seroprevance ranged between 88.0-93.8% in northern, central, and eastern, while it was only 76.1% in southern Taiwan. The seroprevalence of children 0-5 years old were significantly different between free and private vaccination areas. Seropositive children who reported no history of varicella or receiving varicella vaccine accounted for 26.1-59.3% of the total positive cases. Our findings suggest the possible effects of climate, geographical conditions, and lifestyle on the seroepidemiology of VZV in Taiwan. The efforts of implementing a varicella vaccination program in Taiwan should focus on reaching high levels of coverage.

The incidence of varicella in southern Taiwan: a life table method estimation among susceptible population.

Previous studies have failed to estimate the size of population at risk and underestimated the incidence of varicella among susceptible population. In this study, we calculated the incidence of varicella and its complications in Taiwan based on a life table method, in which the size of population at risk was taken into account. Population-based data were obtained from the Bureau of National Health Insurance. The age-specific incidences estimated by the uncorrected and corrected methods were compared. The incidence of varicella increased sharply after infancy and peaked at 16.7% in children aged 5 years. A correction which assumes the introduction of varicella vaccine resulted in a higher incidence of 19.5% in children aged 5 years. The lifetime cumulative incidence increased to around 76%. Sensitive surveillance of varicella and correct incidence estimate among susceptible population are essential in countries that have implemented or are about to implement varicella vaccination.