Cases of thrombosis are more frequent after receiving the vaccine against coronavirus from Astra Zeneca that after that Pfizer / BioNTech, although cases are very rare, according to a study published Thursday.
“After a first dose (of vaccine Astra Zeneca) is observed 30% increased risk of thrombocytopenia compared to a first dose (of the Pfizer / BioNTech vaccine) ” notes the large-scale study published by the British Medical Journal (BMJ).
AIM: Like COVID-19 it can cause premature deaths years later
The thrombocytopenia is a form of thrombosis, namely the formation of a blood clot with life-threatening consequences.
After the launch of vaccination campaigns against COVID-19 since 2021, a link between vial vector vaccines was quickly suspected –Astra Zeneca and Johnson & Johnson – and the occurrence of these blood disorders.
The study, conducted using health data from millions of patients in different countries in Europe and the United States, confirms that these thromboses are more frequent after vaccination of Astra Zenecaeven if they are very rare: 862 cases for more than a million vaccinated.
The risk appears to increase after the first dose. After the second there is no difference between the vaccines Astra Zeneca and Pfizer / BioNTech.
As for the Johnson & Johnson vaccine, the data indicate a higher risk, but not clearly enough for researchers to draw a conclusion.
The study comes above all to confirm “that all vaccines (anticovid) are safe and effective,” microbiologist Sarah Pitt told AFP, highlighting the “extremely rare” frequency of thrombocytopenia cases.