OBJECTIVES: To analyse the in-hospital burden of vaccine-preventable insect-borne diseases with on-going clinical developments and no vaccination alternatives.

METHODS: Firstly, we reviewed ClinicalTrials.gov to identify insect-borne diseases that are experiencing growing clinical research for prevention strategies but without vaccine alternatives. We selected Lyme Disease (LD) and Leishmaniasis. For the analysis we used publicly available aggregated retrospective real-world data of in-hospital diagnoses and length-of-stay (LoS) identified through ICD-10 codes from the Spanish National Hospital Discharge Database (RAE-CMBD) and the Institute for the Hospital Remuneration System (InEK) in Germany. Mean cost/patient was available in RAE-CMBD, but not in InEK, therefore we approximated it using the DRGs associated, their weights and the Bundesbasisfallwerte. Data was available for 2016-2021 for Spain and 2019-2022 in Germany.

RESULTS: In 2021, there were a total number of 5,801 hospitalized cases with a primary diagnostic of LD, 351 in Spain and 5,450 in Germany. Mean LoS and cost/patient were similar (8.22/8.91 days; €3,190/€3,058). LD caused a total hospital economic burden of 17.8€M (16.7€M Germany; 1.1€M Spain). In the same year, a total number of 919 cases of Leishmaniasis were reported, with the majority being in Spain (857). Mean LoS was higher than 10 days in each of the countries. Overall, Leishmaniasis incurred in a 2.9€M total hospital spending (0.2€M Germany; 2.7€M Spain). An increasing trend in hospitalisations due to Leishmaniasis was observed in Spain (+35% from 2016 to 2021) which is consistent with surveillance reports and WHO concerns.

CONCLUSIONS: Insect-borne diseases such as LD and Leishmaniasis caused a substantial burden on hospital resources in 2021 in at least two European countries presenting different healthcare provisioning models. Considering on-going and expected climate changes, increased surveillance of insect-borne diseases and real-world data sharing has the potential to confirm the trends in this analysis and may inform effective resource allocation for prevention.