Burden of adult varicella hospitalizations in Spain (2001-2007)

A population-based retrospective epidemiological study to estimate the burden of adult varicella hospitalizations in Spain was conducted by using data from the national surveillance system for hospital data, Conjunto Mínimo Básico de Datos (CMBD). Records of all adult patients admitted to the hospital with a diagnosis of varicella (ICD-9-MC codes 052.0-052.9) during a 7-year period (2001-2007) were selected. There were 5,450 hospital discharges with a diagnosis of varicella during the study period. The hospitalization rate for the seven-year study period was 2.2 hospitalizations/100,000 people (CI 95% 2.17-2.29). The highest incidence was observed in the 34-45 year age group [4.10 hospitalizations/100,000 people (CI 95% 3.91-4.28)].There were 149 deaths among hospitalised cases in the study period, which represents a mortality of 0.061 deaths/100,000 people (CI 95% 0.05-0.07) and a case-fatality ratio of 2.73% (CI 95% 2.30-3.17)Adult varicella hospitalizations generate an annual expenditure in Spain of 2,962,912 €. Although varicella is mainly a pediatric disease, it causes an important burden of hospitalization in adults. Hospitalization rates related to varicella infection did not vary during the 7-year study period.