Clinical course up to 20 years after hantavirus infection

BACKGROUND: The long-term consequences of nephropathia epidemica (NE), a mild form of hemorrhagic fever with renal syndrome caused by Puumala virus (PUUV), remain incompletely understood. Previous studies suggested possible kidney and cardiovascular complications, but large-scale, long-term data are lacking. METHODS: In this study, we evaluated n = 156 individuals with a history of NE-associated acute kidney injury, up to 20 years after confirmed PUUV infection. Participants were followed up and underwent clinical and laboratory assessments including blood pressure measurement, kidney parameters, urinalysis and PUUV-specific serology. Participants with abnormalities in their kidney function during the first long-term follow-up were re-evaluated after 1 year. RESULTS: Median time since NE was 156 (interquartile range 137-168) months. Chronic kidney disease (CKD) was diagnosed in 8% of participants. Hematuria was present in 6% of participants. Hypertension at follow-up was observed in 78% of individuals. PUUV-specific immunoglobulin G (IgG) antibodies remained detectable in all participants, although three individuals had levels below the positive ratio threshold. No IgM antibodies or cases of reinfection were identified. CONCLUSION: This is the largest and longest follow-up study of NE patients to date. Our findings do not support long-term kidney pathologies, or increased CKD incidence following acute NE. IgG antibodies persisted in all participants irrespective of duration of follow-up, with no evidence of reinfection. While hypertension was frequent, causality with prior hantavirus infection remains uncertain. These results suggest that long-term kidney complications after NE are uncommon.