The effect of TBE Vaccination subsidies on TBE incidence in Sweden

Sammanfattning

Tick-borne encephalitis (TBE) is a growing public health concern in Sweden, despite the availability of an effective vaccine. Several Swedish regions have recently introduced subsidized TBE vaccination programs for children, aiming to increase vaccination uptake and reduce disease incidence. This thesis examines whether regional TBE vaccination subsidies are associated with lower TBE incidence in Sweden. Using panel data for all 21 Swedish regions covering the period 2016–2025, the study applies a difference-in-differences approach with region and year fixed effects to compare regions that introduced subsidies with regions that did not. The analysis is conducted for the total population, children aged 0–18, and adults aged 19 and above. The main specification uses a one-year lagged subsidy variable to account for the delayed protection associated with the TBE vaccination schedule. The results do not provide statistically significant evidence that subsidy programs reduced TBE incidence during the study period. However, the estimated coefficients for the total population and adults are negative and consistent with the theoretical expectation that lower vaccination costs may contribute to lower incidence over time. The findings are limited by short post-treatment periods, low annual incidence levels, and the absence of regional vaccination coverage data.