Background In December 2020 the first European countries initiated their vaccination campaigns with the new COVID-19 vaccines. A cohort event monitoring study in seven European countries was initiated in order to monitor vaccine safety during the roll-out of these vaccines. Objectives The primary aim of the research described in this report is to generate (cumulative) incidence rates of patient-reported ADRs of COVID-19 vaccine brand in near real-time from the pooled European data for the first COVID-19 vaccine campaign in which participants received their first and second dose of the vaccine. This report describes the data available for pooling at the end of October 2021. Study design Participants were recruited, primarily at vaccination sites, in seven countries using three different web apps. Participants were required to fill in a baseline and at least one questionnaire related to adverse reactions. All solicited adverse reactions were coded automatically while unsolicited adverse reactions were coded manually. Serious adverse reactions, adverse events of special interest (AESI) and other reactions needing (medical) clarification were assessed by a qualified assessor. Results The most commonly reported systemic solicited reaction is fatigue which is closely followed by headache and malaise. The types of reported adverse reactions are comparable to the product information however the crude reporting rates varied. A total of 0.2% (0.114, 0.207) of adverse events were reported as serious after first dose; they were uncommon and comparable between the different vaccines, Rates were higher in Germany due to the inclusions of self reported seriousness. Nevertheless, rates of serious adverse reactions were low: 0.7% (0.678, 0.792). The frequency of reporting of AESI were comparable across vaccine brands: roughly 0.1-0.2% of all participants reported an adverse reaction which was considered an AESI. Conclusion The well-known, solicited adverse reactions were reported frequently while reporting of both serious adverse reactions and AESI were low. The initiated Early Covid Vaccine Monitor cohort event monitoring was challenging yet showed that an international collaboration is feasible. As additional (follow-up) data becomes available, further analysis on Covid-19 vaccine safety can be done.

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) with collaboration from the Pharmacovigilance Centre Lareb in the Netherlands. The project has received support from the European Medicines Agency under the Framework service contract nr EMA/2018/28/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. The work in this report is based on: EU PAS Register No: EUPAS39798