Estimating the Under-reporting Factor (URF) of the European ADR Database for COVID Vaccines

The URF is at least 7.2X

EudraVigilance, the European database of suspected adverse drug reaction (ADR) reports is not especially easy to navigate, nor does it have particularly useful breakdowns of the data.

However, there is one section that breaks down ADRs by country and COVID vaccine manufacturer. Cross-referencing this data to the doses given according to the ECDC Vaccine Tracker Portal, it is possible to determine the relative ADR to dose rates for each reporting country.

Assuming that the demographics are similar enough so as not to confound things too much, the range of rates is quite astonishing.

Iceland and the Netherlands have the highest rates for Pfizer-BioNTech, almost 30 times higher than Poland.

Iceland, Austria and the Netherlands have the highest rates for Janssen, over 100 times higher than Romania and Slovakia.

Belgium has the highest rate for Novovax, almost 80 times higher than Czechia.

Iceland, Austria and the Netherlands have the highest rates for Moderna, 40 times higher than Slovakia and Malta.

Finally, Norway and Denmark have the highest rates for AstraZeneca, over 75 times higher than Cyprus.

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Imputing the cases as a function of the URF reveals a URF for the EEA as a whole of around 7.2. With this adjustment, the ADR per 1 million doses rises from 1,500 to 10,795. That’s almost 10 million people who have been suspected to be injured by a COVID vaccine.

It is unlikely that even the highest-reporting country is reporting anywhere near all the ADRs so, in my opinion, 7.2X represents the absolute minimum URF.