New analysis indicates that vaccines greatly reduce hospitalisations for flu and COVID-19
A new modelling study from RespiCompass, the ECDC Respiratory Diseases Scenario Modelling Hub, indicates that influenza and COVID-19 vaccination programmes markedly reduced hospitalisations among older adults across Europe in the 2024/25 season.
The study also reveals stark differences in vaccine uptake between countries, suggesting that much more could be done to reduce pressure on national healthcare systems.
Despite these vaccines being proven to prevent severe illness, influenza vaccination rates in most EU/EEA countries remain below the World Health Organization (WHO) targets for at-risk groups, and COVID-19 vaccination rates continue to fall.
RespiCompass worked with several international modelling teams to conduct this analysis, combining their models to simulate different scenarios. Their shared results complement clinical vaccine effectiveness studies and offer practical evidence on the impact of vaccination for national public health agencies, vaccination programme managers, healthcare workers, and science communicators to strengthen future vaccination strategies.
Additional collaborative modelling studies like this one can also support cost-effectiveness studies, resource planning and stronger public health communication at both EU/EEA and national levels.
Key findings
Between 5 August 2024 and 1 June 2025, vaccination programmes in EU/EEA countries were projected to:
- Prevent 26–41% of flu-related hospitalisations among adults aged 65 and over;
- Reduce COVID-19 hospitalisations in the same age group by 14–20%.
These projections assumed that vaccine effectiveness against hospitalisation was 60% for influenza vaccines and 75% for COVID-19 vaccines. These rates were chosen based on the latest available evidence. The percentage of averted hospitalisations varied because of differing vaccine uptake levels and assumptions on transmissibility and immunity waning.
These findings show that there is still a lot of untapped potential to reduce hospital pressure through both long-standing measures like seasonal flu vaccination and newer programmes such as COVID-19 vaccination. Moreover, they underline that even small increases in vaccine uptake can lead to meaningful reductions in hospitalisations.
