COVID-19 and blood clotting risks

An image spreading on social media refers to hospital patients.

With concerns over rare blood clots, Denmark suspends use of the Oxford-AstraZeneca vaccine. An image comparing the ‘risk of blood clots’ spreads:

The sources are on the bottom. (Image: Twitter)

We can translate sources for each number:

Oxford-AstraZeneca (Vaxzevria) vaccine

The source is either unstated or incorrect. The estimate is from the UK’s Medicines and Health products Regulatory Authority:

By 31 March 20.2 million doses of the COVID-19 Vaccine AstraZeneca had been given in the UK meaning the overall risk of these blood clots is approximately 4 people in a million who receive the vaccine.

The European Medicines Agency used a figure from the Paul-Ehrlich-Institut in Germany. Their estimated rate was about one in 100,000 vaccinations. Disparities between national estimates come from coverage, case definition, periods, and population differences.

In general, blood clots can range from mild to life-threatening. The incidence refers to unusual blood clotting with low platelets. Another name is vaccine-induced immune thrombotic thrombocytopenia (VITT). There is building evidence of the importance of age and these rare and serious blood clots…