Search results for "Chickenpox"
showing 10 items of 27 documents
The epidemiology of Varicella Zoster Virus infection in Italy
2008
Abstract Background The epidemiological importance of varicella and zoster and the availability of an efficacious and safe vaccine have led to an important international debate regarding the suitability of mass vaccination. The objective of the study was to describe the epidemiology of varicella and zoster in Italy and to determine whether there have been changes with respect to observations provided by an analogous study conducted 8 years ago, in order to define the most appropriate vaccination strategy. Methods A number of data sources were evaluated, a cross-sectional population-based seroprevalence study was conducted on samples collected in 2004, and the results were compared with data…
The impact of ten years of infant universal Varicella vaccination in Sicily, Italy (2003-2012).
2015
Introduction Universal varicella vaccination in Sicily was introduced in infant population since 2003, with a rapidly increasing coverage. Aim of the present study was to analyze changes in the epidemiology of varicella since the introduction of universal vaccination. Methods The study was performed by analyzing Sicilian administrative/clinical data on varicella case notifications and hospitalizations from 2003 to 2012 (ICD-9-CM discharge diagnosis codes 052 and 052.×). MMR+V and V coverage were also calculated for each birth cohort. Moreover, blood samples drawn in 2013/2014 from general population stratified by age were tested for varicella antibodies. Results From 2003 to 2012, 15 433 va…
Modeling Chickenpox Dynamics with a Discrete Time Bayesian Stochastic Compartmental Model
2018
[EN] We present a Bayesian stochastic susceptible-exposed-infectious-recovered model in discrete time to understand chickenpox transmission in the Valencian Community, Spain. During the last decades, different strategies have been introduced in the routine immunization program in order to reduce the impact of this disease, which remains a public health's great concern. Under this scenario, a model capable of explaining closely the dynamics of chickenpox under the different vaccination strategies is of utter importance to assess their effectiveness. The proposed model takes into account both heterogeneous mixing of individuals in the population and the inherent stochasticity in the transmiss…
Coverage, efficacy or dosing interval: which factor predominantly influences the impact of routine childhood vaccination for the prevention of varice…
2016
Background Varicella is a highly infectious disease with a significant public health and economic burden, which can be prevented with childhood routine varicella vaccination. Vaccination strategies differ by country. Some factors are known to play an important role (number of doses, coverage, dosing interval, efficacy and catch-up programmes), however, their relative impact on the reduction of varicella in the population remains unclear. This paper aims to help policy makers prioritise the critical factors to achieve the most successful vaccination programme with the available budget. Methods Scenarios assessed the impact of different vaccination strategies on reduction of varicella disease…
A Bayesian unified framework for risk estimation and cluster identification in small area health data analysis.
2020
Many statistical models have been proposed to analyse small area disease data with the aim of describing spatial variation in disease risk. In this paper, we propose a Bayesian hierarchical model that simultaneously allows for risk estimation and cluster identification. Our model formulation assumes that there is an unknown number of risk classes and small areas are assigned to a risk class by means of independent allocation variables. Therefore, areas within each cluster are assumed to share a common risk but they may be geographically separated. The posterior distribution of the parameter representing the number of risk classes is estimated using a novel procedure that combines its prior …
Spatio-temporal cluster detection of chickenpox in Valencia, Spain in the period 2008-2012.
2015
Chickenpox is a highly contagious airborne disease caused by <em>Varicella zoster</em>, which affects nearly all non-immune children worldwide with an annual incidence estimated at 80-90 million cases. To analyze the spatiotemporal pattern of the chickenpox incidence in the city of Valencia, Spain two complementary statistical approaches were used. First, we evaluated the existence of clusters and spatio-temporal interaction; secondly, we used this information to find the locations of the spatio-temporal clusters via the space-time permutation model. The first method used detects any aggregation in our data but does not provide the spatial and temporal information. The second me…
Coverage rates against vaccine-preventable diseases among healthcare workers in Sicily (Italy)
2020
Abstract Background Vaccination of healthcare workers (HCWs) reduces the risk of occupational vaccine-preventable diseases (VPDs), prevents their nosocomial transmission and preserves healthcare delivery during outbreaks. Extensive implementation of vaccination programmes for HCWs allowed the elimination or control of several VPDs within healthcare facilities; despite these, the vaccine adherence rates among HCWs are persistently suboptimal. Methods A questionnaire was self-administered by HCWs to assess their vaccination rates against several VPDs and self-reported immunity in two university hospitals of Southern Italy (Catania and Palermo). Results A total of 2586 questionnaires were anal…
Cytomegalovirus and varicella–zoster virus vaccines in hematopoietic stem cell transplantation
2009
Impairment of cellular immunity upon hematopoietic stem cell transplantation (HSCT) may lead to serious clinical manifestations induced by human cytomegalovirus (HCMV) and varicella-zoster virus (VZV) infections. Although the clinical presentations, preferential organ involvement and clinical courses are different, infections with both herpesviruses are similar with respect to many pathophysiological aspects and the therapeutic strategies that are employed to combat them. Antiviral drug prophylaxis and therapy are successfully used to limit the risk of reactivated HCMV and VZV infections, but are unable to absolutely prevent episodes of virus disease in long-term follow-up after HSCT. Contr…
Has VZV epidemiology changed in Italy? Results of a seroprevalence study
2017
The aim of the study was to evaluate if and how varicella prevalence has changed in Italy. In particular a seroprevalence study was performed, comparing it to similar surveys conducted in pre-immunization era. During 2013–2014, sera obtained from blood samples taken for diagnostic purposes or routine investigations were collected in collaboration with at least one laboratory/center for each region, following the approval of the Ethics Committee. Data were stratified by sex and age. All samples were processed in a national reference laboratory by an immunoassay with high sensitivity and specificity. Statutory notifications, national hospital discharge database and mortality data related to V…
Space-time airborne disease mapping applied to detect specific behaviour of varicella in Valencia, Spain.
2015
Airborne diseases are one of humanity's most feared sicknesses and have regularly caused concern among specialists. Varicella is an airborne disease which usually affects children before the age of 10. Because of its nature, varicella gives rise to interesting spatial, temporal and spatio-temporal patterns. This paper studies spatio-temporal exploratory analysis tools to detect specific behaviour of varicella in the city of Valencia, Spain, from 2008 to 2013. These methods have shown a significant association between the spatial and the temporal component, confirmed by the space-time models applied to the data. High relative risk of varicella is observed in economically disadvantaged region…