Implementation of Data Linkage in Crete, Greece: a pilot study within the EUVABECO Project

Background

Health relevant data are fragmented across multiple databases and managed by different services. The European Vaccination Beyond COVID-19 (EUVABECO) project (https://euvabeco.eu/), aims to support vaccination systems across European Union Member States by implementing five tools, including Data Linkage. This integrates individual-level data to e.g. support targeted vaccination of high-risk populations. High-risk groups are key to identify in health system preparedness during crises. This study presents results from the pilot implementation of Data Linkage in Crete, Greece.

Methods

The pilot used the data linkage processed tested in the Project implementation plan to link hospital data to assess COVID-19 vaccination uptake among vulnerable patients aged over 75, including those with multimorbidity, polypharmacy, or residing in remote areas of Crete, hospitalized for COVID-19 at a tertiary hospital in Heraklion during 2020–2024. Data linkage was performed using a unique identifier across two hospital databases: an administrative database (demographics) and a hospital information system (clinical records).

Results

A total of 1.115 patients over 75 years, were hospitalized due to COVID-19 during 2020-2024, with 47.1% female 47.4% male and 5.5% missing data. Of these, 69% were classified as having an additional vulnerability due to multimorbidity, polypharmacy or living in remote areas. Vaccination status among vulnerable patients was 14.4% vaccinated, 3.3% unvaccinated, and 82.3% with missing data. 16.4% were vaccinated and lived in remoted areas and 24.2% were vaccinated and lived in urban. Regarding clinical outcomes, 82% recovered, 1.6% unchanged, 0.3% worsen and cured and 16.3% died.

Conclusions

Despite this pilot challenges regarding fragmented databases and missing data, it may support real-time situational awareness, support targeted vaccination strategies for high-risk populations and public health planning in Crete and Greece.

Key messages

• Data linkage in Crete revealed major gaps in vaccination and clinical data, particularly a high level of missing vaccination status among vulnerable older COVID-19 patients.

• Despite limitations, it demonstrated strong potential to support real-time surveillance and targeted vaccination strategies for high-risk populations.