Thrombosis is a disease that affects 300,000 people in France each year. It corresponds to the formation of a clot which can go so far as to block an artery or a vein and prevent the proper circulation of blood.
- It starts with platelets that we have in the blood which will aggregate with each other until they form a clot which can, depending on its size, partially or completely block a vein or an artery.
- The most common is phlebitis, which affects the veins located in the legs.
- In the context of the AstraZeneca vaccine, what worries health authorities is a possible link between the vaccine and cases of cerebral venous thrombosis.
Like dominoes, many European countries have in turn suspended the use of the vaccine developed by the Swedish laboratory AstraZeneca with researchers from the British University of Oxford. The reason: several cases of thrombosis appeared a few days after the injection of the product. Studies are underway within the European Medicines Agency to assess the risk and issue an opinion, expected this Thursday.
From thrombosis to pulmonary embolism
Thrombosis is the formation of blood clots. In France, this pathology is common and affects approximately 300,000 people each year. It starts with platelets that we have in the blood which will aggregate with each other until they form a clot which can, depending on its size, partially or completely block a vein or an artery. When it affects a vein, we speak of venous thrombosis, the most common of which is phlebitis, which concerns the veins located in the legs. Phlebitis is manifested by pain in the calf which becomes red, hot and painful.
In some cases, the thrombosis can become very serious and the clot can migrate, end up in the lungs and cause a pulmonary embolism which can lead to respiratory distress or even cardiac arrest. A simple ultrasound can diagnose it. Early detection is essential to prevent the condition from getting worse and the clot blocking vital blood vessels. Anticoagulants are the most effective treatment and help thin the blood to prevent the appearance of new clots.
Suspected cerebral venous thrombosis linked to AstraZeneca
In the context of the AstraZeneca vaccine, what worries health authorities is a possible link between the vaccine and cases of cerebral venous thrombosis. “The risk is very low. But if these cases were to be linked to vaccination, it would be a higher than average risk.”, underlined the German Minister of Health, Jens Spahn, referring to the occurrence of 7 cases of cerebral thrombosis out of 1.6 million doses of AstraZeneca administered on its territory. In normal times, on such a population, we should statistically have “about 1 to 1.4 cases” cerebral venous thrombosis. In all, the European Medicines Agency is studying the relationship between AstraZeneca injections and 11 cases of cerebral venous thrombosis detected among 17 million people vaccinated in the European Union.
Despite these fears, the EMA said it was “firmly convinced” benefits of the AstraZeneca vaccine against Covid-19. The World Health Organization (WHO), which is also looking into the subject, also continues to recommend the use of this serum. Furthermore, it is established that the virus itself can cause blood clots. “Some of the clotting issues currently being seen may have been caused not by the vaccine, but by Covid”advances Professor Stephen Evans of the London School of Hygiene & Tropical Medicine, quoted by the British organization Science Media Center.
.