frequent group to experience severe outcomes of COVID-19, including death, and have therefore been prioritised for vaccination. Vaccine prioritisation has also involved those working in long-term healthcare facilities, including staff, due to their frequent contact with vulnerable residents. Studies performed in long-term care facilities can be therefore be useful for understanding whether the vaccines can reduce symptomatic COVID-19 infection, severe COVID-19, deaths due to COVID-19, and transmission of SARS- CoV-2. 

## Lot 4. Vaccine effectiveness and impact of COVID-19 vaccines through routinely collected exposure and outcome data using health registries 

Currently, vaccination is targeting specific groups of the population like elderly and healthcare workers but should in the short-term be expanded to all adults as routine vaccination. 

Throughout the EU/EEA, a majority of countries have available digital solutions 9 for the recording of individual vaccination data that are being also used currently to record exposure to COVID-19 vaccines. 

These solutions may allow a continuous assessment of the vaccine effectiveness and impact against respiratory infections caused by SARS-CoV-2, including by linkage of individual vaccination data with health outcome data. 

## Lot 5. Vaccine effectiveness against COVID-19 and seasonal influenza among patients presenting to primary care physicians in EU/EEA 

Seasonal influenza and COVID-19 pose a significant burden of disease on European populations. Influenza, due to its seasonal epidemic peaks causes significant healthcare pressures on primary care facilities. As of February 2021, it is difficult to estimate what the future epidemiology of COVID-19 will be, but it is possible that continuous or seasonal circulation of the virus will continue for years to come. The majority of individuals infected with either influenza or SARS-CoV-2 recover after a brief respiratory or systemic illness, and do not need admission to healthcare facilities. The propensity for seeking primary care consultations is dependent on availability of services, available treatment, potential parallel pathways to care, as established for COVID-19 and healthcare seeking behaviour. Most efforts to assess vaccine effectiveness for seasonal influenza have been based on study sites that are included in various influenza sentinel surveillance systems. The EU/EEA disease surveillance systems originally designed for influenza have been adapted to capture information on COVID-19. ECDC has since 2007 commissioned annual influenza vaccine effectiveness studies against seasonal influenza. There is a need to complement the existing efforts to estimate seasonal influenza vaccine effectiveness in primary care with integration of both seasonal influenza and COVID-19 VE assessments, which will allow for estimation of the impact the vaccines on mild disease. 

## 2.1.3 Conclusion 

In the light of the above, ECDC plans to support the assessment of effectiveness of vaccines against COVID- 19 by establishing or enhancing an infrastructure and by conducting studies in the EU/EEA Member States and EU candidates and potential candidates in Western Balkan region 10  among different settings. In the settings where the infrastructure can benefit from ongoing and previous efforts (SARI surveillance, primary care) influenza vaccine effectiveness will also be evaluated. Studies on the impact of interventions such as vaccination programmes will complement the vaccine effectiveness studies to inform decision making. 

