Assessing the annual burden of tick-borne encephalitis virus infections, north-east Italy, 2017 to 2024

BACKGROUND Tick-borne encephalitis (TBE), a neuroinvasive disease in humans, is endemic in north-east Italy and nationally notifiable since 2017. Domestic TBE incidence, although low, has increased in recent years while TBE vaccination coverage remains < 10%. AIM We aimed to estimate the burden of TBE virus (TBEV) infections in north-east Italy (Triveneto) in 2017–2024. METHODS We estimated disability-adjusted life years (DALYs) with 95% uncertainty intervals (UI) using the Burden of Communicable Diseases in Europe software. Input data included TBE cases notified in 2017–2024 with residence and/or infection or exposure in Triveneto (autonomous provinces (AP) of Trento and Bolzano and regions of Veneto and Friuli-Venezia Giulia) and correction factors for TBE underdiagnosis and TBEV infection under-ascertainment. RESULTS In 2017–2024, 295 TBE cases were notified in Triveneto. The mean annual burden of TBEV infections was estimated at 0.58 (95% UI: 0.55–0.62) DALYs per 100,000 population. Estimates were highest in 2022 (1.07; 95% UI: 1.00–1.14 DALYs/100,000). The areas with the highest burden were Belluno province (4.17; 95% UI: 3.88–4.46 DALYs/100,000/year) and the AP of Trento (2.84; 95% UI: 2.65–3.05 DALYs/100,000/year). Males accounted for 67.0% of DALYs. All age groups experienced on average ≤ 1 DALYs per 100,000 population per year. CONCLUSION The burden of TBEV infections in north-east Italy is relatively low and with an uneven geographical distribution. Increasing TBE vaccination coverage across age groups, prioritising elevated impact areas, may reduce the burden of TBEV infections in north-east Italy and maintain TBE as a low-burden disease.