Those vaccinated with AstraZeneca should continue with a second dose of the same vaccine, if no adverse reactions occurred after the first dose, Prof. Mariana Murdzheva, rector of the Medical University in the city of Plovdiv and a member of the National Vaccine Task Force, has told Radio Plovdiv. It is known that thrombosis is well known clinical reaction. For example, it occurs with the Ebola vaccine. So far, the European Medicines Agency has not reported any cases of thrombosis after a second dose of Astra Zeneca vaccine, Prof. Mariana Murdzheva said. "The risk of thrombosis is many times lower than the risk of infection," she added.