Core protocol for ECDC studies of COVID-19 vaccine effectiveness against hospitalisation with Severe Acute Respiratory Infection laboratory-confirmed with SARS-CoV-2, version 1.0
This core protocol is primarily intended to guide the implementation of ECDC-funded studies. However, ECDC would like to encourage the use of this protocol as a basis for other vaccine effectiveness studies in countries/hospitals that do not currently plan to participate in ECDC-funded studies. The use of consistent protocols will facilitate the comparability of study results across studies, countries, and study sites.
Executive summary
The end of 2019 saw the emergence of a novel severe acute respiratory syndrome: coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19). As of week 38 2021, over 37 million cases and more than more than 750 000 deaths had been reported in the European Union/European Economic Area (EU/EEA).
As of week 38 2021, four vaccines (Comirnaty, Spikevax [previously COVID-19 vaccine Moderna], Vaxzevria, and Janssen) have been authorised by the European Commission based on the scientific opinion of the European Medicines Agency (EMA) for use in the European Union, and many others are under rolling review.
In 2020, the European Commission emphasised the importance of continuously monitoring the safety and effectiveness of vaccines in the EU/EEA and called on ECDC and EMA to develop a structured post-authorisation monitoring platform for vaccines, prioritising COVID-19 vaccines. In November 2020, the European Commission proposed to the European Parliament and the Council of the EU a change to the mandates of EMA and ECDC in the context of its COVID-19 lessons learned package and the creation of a European Health Union, empowering the two agencies to jointly coordinate independent vaccine monitoring studies.
As a result, at the end of 2020, utilising the lessons learned from other vaccine effectiveness studies, ECDC started building infrastructure to perform COVID-19 vaccine effectiveness studies. The infrastructure aims to build a system to regularly monitor vaccine effectiveness and perform studies in different settings, and depending on the setting, to provide information on different outcomes (severe disease, moderate disease, transmission, etc).
This core protocol for ECDC studies of COVID-19 vaccine effectiveness against hospitalisation with Severe Acute Respiratory Infection laboratory-confirmed with SARS-CoV-2, version 1.0, presents the main elements for a multicentre (multi-country) hospital-based study of COVID-19 vaccine effectiveness in patients hospitalised with Severe Acute Respiratory Infection, outlining the agreed methods for collecting data related to COVID-19 and SARS-CoV-2 at country level, and includes a plan for the pooled analysis. The combination of data from multiple sites will allow for studies with more statistical power to meet more specific objectives.
This core protocol, therefore, is primarily intended to guide the implementation of ECDC-funded studies. However, ECDC would like to encourage the use of this protocol as a basis for other vaccine effectiveness studies in countries/hospitals that do not currently plan to participate in ECDC-funded studies. The use of consistent protocols will facilitate the comparability of study results across studies, countries, and study sites.
This document presents version 1.0 of the core protocol, which is planned to be updated and revised on a regular basis and subsequently implemented at country level.
