Thirty cases of rare blood clotting have been recorded in Britain among more than 18 million people who have had the AstraZeneca vaccination, the national medicines regulator said Friday Up to 24 March, 22 reports of cerebral venous sinus thrombosis and eight of other thrombosis events with low platelets were logged, the Medicines and Healthcare products Regulatory Agency said. "The risk of having this specific type of blood clot is very small," it added, urging the public to continue to take the vaccination. mpa/lpt/bp/har