Mortality Rate Patterns for Hemorrhagic Fever with Renal Syndrome Caused by Puumala Virus

To investigate nephropathia epidemica in Sweden during 1997-2007, we determined case-fatality rates for 5,282 patients with this disease. Overall, 0.4% died of acute nephropathia epidemica ≤3 months after diagnosis. Case-fatality rates increased with age. Only women showed an increased case-fatality rate during the first year after diagnosis.