In January 2021, the European Medicines Agency (EMA) launched a tender for safety monitoring of COVID-19 vaccines in the EU. The EU PE & PV and the VAC4EU network received and implemented the tender, which had two objectives, the first was to implement a prospective cohort for safety monitoring in more than 10 countries and the second was signal strengthening. This report is focusing on the second objective. Based on the technical specifications, signal strengthening meant the collection of additional information to further characterise the incidence of the safety concerns in comparison to its expected incidence in non- vaccinated populations or suitable comparator populations. Request of signal strengthening capacity was translated into two objectives: i) to create and assess readiness of electronic healthcare record data sources for rapid evaluation of safety signals by providing an overview of the methods to identify COVID-19 vaccine exposure in data sources, monitoring the number of individuals exposed to any COVID-19 vaccine, and the generation of updated background rates for Adverse Events of Special Interest, and ii) to conduct rapid safety assessment studies using electronic healthcare records and support EMA safety assessments.

The research leading to these results was conducted as part of the activities of the EU PE&PV (Pharmacoepidemiology and Pharmacovigilance) Research Network (led by Utrecht University) in collaboration with the Vaccine Monitoring Collaboration for Europe network (VAC4EU). Scientific work for this project was coordinated by the University Medical Center Utrecht. The project has received support from the European Medicines Agency under the Framework service contract nr EMA/2018/23/PE. This report expresses the opinion of the authors and may not be understood or quoted as being made on behalf of or reflecting the position of the European Medicines Agency or one of its committees or working parties. Work in this report is based on: EU PAS Register No. EUPAS42467