U.K. and Europe Updated COVID Vaccine Adverse Event Data

The United Kingdom and European Union posted updated adverse events statistics in late January showing people in those regions are continuing to report problems at an unusually high rate after taking mRNA vaccines.

U.K. Adverse Events

The data show that as of January 19, the U.K. Yellow Card system reported 1,552,248 adverse events, mostly associated with Pfizer BioNTech’s mRNA vaccines (1,286,984), followed by AstraZeneca (231,168), Moderna (32,936), and unspecified vaccines (1,160).

European Adverse Events

The European Medicines Agency’s latest EudraVigilance update on January 24 reported a total of 1,428,060 adverse event reports, led by cases associated with Pfizer BioNTech (722,454), followed by AstraZeneca (442,029), Moderna (215,196) and Janssen (48,381).

Most EU Adverse Events Involve Ages 18-64

More than three-quarters of adverse events involved subjects between 18-64 years of age. The second leading cohort, about 15 percent, was between 65-85 years of age.

The U.K.’s Yellow Card and EU’s EudraVigilance systems are counterparts to the Vaccine Adverse Events Reporting System run by the United States Centers for Disease Control (CDC) and the Food and Drug Administration (FDA) which tracks adverse events associated with vaccines.

Adverse Event Rates in U.K. Vs. Europe Are Disproportionate

Adverse event registries are deemed to be passive surveillance systems since they rely on reporting by health workers or individuals experiencing suspected adverse events. This passive system has led researchers to conclude they typically undercount real world cases. 

Others have noted that proving adverse events is a difficult prospect since there may be many reasons for a sickness or death around the timeframe that an individual has been vaccinated.

One sign of the difficulty of tracking adverse events is the massive disparities seen across jurisdictions with similar rates of vaccination. For example, the U.K. has 68 million residents and 1,552,248 adverse effect reports, compared to the EU, which has 440 million residents and 1,428,060.