Clinical and cost characterization of hospitalization associated with varicella in children from the Metropolitan Region and Valparaíso, Chile

Abstract

Background: Varicella is a relevant infection in Chile and may cause serious complications and death, which could be associated with significant health care resource utilization and associated costs. In Chile, sentinel surveillance is carried out only on an outpatient basis, without knowing the impact of varicella in serious cases who need to be hospitalized. Aim: To describe the clinical characteristics and the costs associated with hospitalized children with diagnosis of varicella prior to the vaccine introduction in the National Immunization Program in Chile. Patients and Methods: A multicenter, observational, and retrospective study in hospitalized children (0-15 years) with a diagnosis of varicella, were conducted in five hospitals in Chile between January 2011 and December 2015. A review of the clinical records was performed to evaluate the clinical characteristics of the disease and costs associated with hospitalization episodes for varicella. Results: A total of 685 hospitalized children for varicella were included in this study. The median age was 3 years (IQR: 1-5), most children were between 1 and 4 years of age (52% of total cases). 56% were male, and only 7 patients (1%) had a history of previous varicella vaccination. The median lenght of days of hospitalization was 3 days (IQR: 2-5). 13% of the cases required hospitalization in a more complex care unit, 6% in the intermediate unit and 7% in the pediatric intensive treatment unit, both with a median stay of 3 days. The main complications were: skin and soft tissue infections (42%),neurologic (8%) and septic or toxic shock (4%). There were 3 cases of death (0.4%). The direct cost of a varicella case was US $ 417, the indirect cost was US $ 224 and the proportional cost of a case of death was US $ 3,575. It is estimated that the total cost of a hospitalized varicella case in Chile was US $ 4,216. Conclusions: Varicella is associated with a significant burden of disease in Chile. The median hospital stay was three days with 13% of cases requiring medical care in a complex unit, with high associated costs which could be significantly reduced with the recently incorporation of the varicella vaccine into the National Immunization Program.