COVID-19 Vac­cine Vaxzevria (As­traZeneca) - Pos­si­ble Link with Very Rare Cas­es of Un­usu­al Blood Clots in Com­bi­na­tion with Low­ered Platelet Counts

COVID-19 Vaccine (Source: Insta_Photos/

The Pharmacovigilance Risk Assessment Committee (PRAC) at the European Medicines Agency (EMA) has further investigated the very rare cases of thrombosis in combination with a decreased platelet count (thrombocytopenia) and, in some cases, of severe bleeding in individuals after vaccination with Vaxzevria (formerly COVID-19 vaccine AstraZeneca) and has published the results so far available on 07 April 2021. The Paul-Ehrlich-Institut is represented on the PRAC.

The PRAC concluded today that the occurrence of unusual blood clots with decreased platelet counts should be included in the Summary of Product Characteristics (SmPC) as a very rare adverse reaction of Vaxzevria.

The PRAC further notes that COVID-19 is associated with a risk of severe courses with hospitalisation and death. The reported combination of blood clots and decreased platelets is very rare, and the overall benefit of the vaccine in preventing COVID-19 outweighs the risks of its side effects.

Rare thromboses observed (with thrombocytopenia) included venous thromboses in unusual sites such as large cerebral veins (sinus vein thromboses), intestinal veins (splanchnic veins), and arterial thromboses. Most of the cases reported to date have occurred in persons under 60 years of age within two weeks of receiving the first dose. To date, there has been limited experience with the second dose. At this time, it has not been possible to identify specific risk factors.

In Germany, AstraZeneca's Vaxzevria vaccine is recommended by the Standing Committee on Vaccination (STIKO) exclusively for persons 60 years of age and older. The recommendation is based on intensive analyses of the current data situation, taking into account the current pandemic situation. The above PRAC conclusions are in line with the European approval, the current recommendation of the STIKO and the evidence base of the Paul-Ehrlich-Institut in Germany.

Updated: 15.04.2021