Epidemiology and economic burden of Puumala virus infection in Styria, Austria, 2003 to 2024

Background Hantavirus infections cause hemorrhagic fever with renal syndrome and impose a potential burden on healthcare systems. However, comprehensive economic data remain scarce. We quantified the inpatient economic burden of hospitalized patients with Puumala virus (PUUV) infections in Styria, Austria´s primary endemic region, to identify hospitalization costs and early admission predictors of costs. Methods This retrospective cost-of-illness study analyzed 1,049 serologically confirmed PUUV hospitalizations across 20 public hospitals in Styria, Austria between September 2003 and March 2024. Costs were estimated using the Austrian performance-oriented hospital financing (LKF) diagnosis-related-group-system, standardized to 2024-equivalent Euros using consumer-price-index deflation. Admission predictors of cost were assessed using multivariable γ-generalized-linear-modeling with multiple imputation. Temporal trends in length of stay were analyzed using weighted segmented linear regression. Results Cumulative inpatient cost was approximately €10.3 million (mean per-case: €9,788) for the entire study period of 21 years. Three epidemic years (2012, 2019, 2021) accounted for 53.6% of cases and over €5.2 million in expenditure, with peak annual costs reaching €1.93 million (0.274% of total Styrian inpatient expenditure) in 2012. Prolonged activated partial thromboplastin time (aPTT; cost-ratio 1.024 per second, 95% CI 1.019–1.030) and older age (CR 1.004 per year, 95%-CI 1.001–1.008) were independent admission-level predictors of higher cost. Median hospital length of stay declined by approximately 50% over the study period. Conclusions PUUV hospitalizations impose a sharply episodic but recurrent economic burden on regional healthcare systems. Admission aPTT and age independently predicted cost, but clinical outcomes were not modelled and these variables do not constitute a triage tool. Epidemic preparedness strategies are warranted.