Varicella-related Hospitalizations in Turkey
Condition: Chickenpox
MeSH terms: Chickenpox; Herpes Zoster
Study type: Observational

Summary: 
      Epidemiological information on varicella complications in children is essential for the
      development of appropriate immunization recommendations. Economic analyses of varicella
      immunization are sensitive to the costs of hospitalized cases, so there is a need to validate
      varicella-related hospitalization data in a country-specific manner. These data also provide
      a baseline for comparison with data collected after routine varicella immunization to
      evaluate the overall impact and cost-effectiveness of varicella immunization programs.
      Knowledge about the cause and incidence of varicella-related hospitalizations in Turkey is
      limited, center-specific and not sufficiently accurate. The aim of this multicenter study
      (VARICOMP) was to estimate the annual incidence of pediatric varicella-related
      hospitalization, describe the associated complications and estimate the annual mortality and
      economic cost of these cases.
    

Detailed description: 
      Varicella infection is one of the common childhood infectious disease. While usually
      self-limiting, a case of varicella can develop complications -sometimes potentially serious-
      requiring hospitalizations including secondary bacterial infections (mainly at the skin and
      skin structure), respiratory complications (pneumonia or exacerbation of asthma),
      neurological complications (encephalitis and cerebellitis). Most hospitalizations for
      varicella occurred in children who were previously healthy and can cause significant long
      term sequele and mortality in immunocompetent as well as immunocompromised children.
      Incidence of varicella and related hospitalization rates changes according to climates and
      also the presence of vaccination. WHO recommended that routine childhood varicella
      vaccination be considered in countries where the disease is a relatively important public
      health and socioeconomic problem however live attenuated varicella introduced to the
      childhood immunization programmes in Australia, Canada, Germany, Greece, Qatar, Republic of
      Korea, Saudi Arabia, Taiwan, United States, Uruguay, and parts of Italy and Spain. Clinically
      and statistically significant reduction in varicella-related hospitalizations for children
      and adults associated with childhood varicella immunization and a corresponding significant
      decrease in hospital charges.

      Epidemiological information on varicella complications in children is essential to develop
      immunization recommendation strategies. Economic analyses of varicella immunization are
      sensitive to the costs of hospitalized cases, so there is a need to validate varicella
      related hospitalization data at the country-based level. The data also provide a baseline for
      the data after routine varicella immunization to evaluate the overall impact and
      cost-effectiveness of varicella immunization programs. Knowledge about the cause and
      incidence of varicella related hospitalization are limited and center-specific in Turkey and
      cannot provide sufficiently accurate information. Varicella infections have been commonly
      seen in children in Turkey and VZV seroprevalence increased with age and 70% at the age of 7
      years and 90% in 15-19 years. Varicella vaccine is available in private practice in Turkey
      and estimated coverage is lower than 10%.

      The aim of this multicenter study (VARICOMP study) to estimate the annual incidence of
      pediatric varicella related hospitalizations, describe the complications and estimate annual
      mortality and cost in children.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        0-18 years old hospitalized children due to varicella and -related complications
      
Keywords: Varicella; Turkey; hospitalization; varicella vaccine