RELEVANCE OF COMPLICATIONS AS COST DRIVERS OF VARICELLA

OBJECTIVES: For many diseases, a small number of complicated cases accounts for the main part of the costs. Our aim was to investigate the relevance of complications for the overall costs of varicella in Germany in order to assess whether vaccination strategies targeting at risk groups, e.g. adolescents, have the potential to substantially reduce the economic burden of varicella. METHOD: A decision-analytic model, the Economic Varicella VaccInation Tool for Analysis (EVITA), was used to analyze epidemiological and economic effects of varicella over a period of 30 years as varicella incidence fluctuates over time and, thus, a typical cost of illness study performed in one year might provide biased estimates of overall costs. Input data on the epidemiology of varicella and its complications as well as the respective resource use were derived from two large surveys. RESULTS: Complications occur in 5.7% of the annual average of 739,000 cases. Overall annual costs are €187.5 million from the societal and €78 million from the payers' perspectives. From the payers' (societal) perspective 32.0% (24.7%) of the overall costs can be attributed to complications. Complications account for 53.8% (53.3%) of the direct medical costs and 15.5% (18.3%) of the indirect costs. When complications occur, inpatient care (67.7%) from the payers' and work loss (60.9%) from the societal perspectives are the main cost drivers of complications. Pneumonia accounts for the majority of the costs of complications. For uncomplicated courses of varicella, the indirect costs of work loss are the major cost factor. CONCLUSIONS: Complications account for a disproportionate part of overall disease costs. However, uncomplicated courses account for the vast majority of costs. Vaccination strategies targeting only on risk groups with high risks of complications might therefore fail to substantially reduce the considerable economic burden of varicella.