The European Medicines Agency (EMA) has recommended granting a conditional marketing authorisation for Oxford-AstraZeneca COVID-19 Vaccine to prevent coronavirus disease 2019 (COVID-19) in people from 18 years of age and older with no upper age limit. WHO has similarly listed Oxford-Astra Zeneca vaccine for emergency use.
Recently, rare cases of severe thrombosis and thrombocytopenia, some presenting as mesenteric vein or cerebral vein/cerebral venous sinus thrombosis, have been reported in persons who had recently received COVID-19 Oxford – AstraZeneca vaccine, mostly occurring within 14 days after vaccination. The majority of reports involved women under 55, although some of this may reflect greater exposure of such individuals due to targeting of particular populations for vaccine campaigns in different Member States. After reviewing the data of more than 25 million vaccinated people, EMA concluded that the vaccine is not associated with an increase in the overall risk of blood clots (thromboembolic events) in those who receive it. However, Vaxzevria may possibly be associated with very rare cases of specific embolic and thrombotic events, including disseminated intravascular coagulation and cerebral venous sinus thrombosis in combination with low levels of blood platelets (thrombocytopenia) and related bleeding. While the Agency continues to investigate this possible association with very rare severe thromboembolic events and thrombocytopenia, occurring in less than 1 per million vaccinated to date, a warning on this very rare event has been included in the product information. Nevertheless, EMA considers that the benefit-risk balance of the vaccine remains positive and vaccination should continue normally.
Health care personnel should be alert to the signs and symptoms of thromboembolism and or thrombocytopenia. Those vaccinated should be instructed to seek immediate medical attention if they develop symptoms such as shortness of breath, chest pain, leg swelling, persistent abdominal pain following vaccination. Additionally, anyone with neurological symptoms including severe or persistent headaches and blurred vision after vaccination, or who experience skin bruising (petechia) beyond the site of vaccination after a few days, should seek prompt medical attention.