No cases of a blood clotting disorder have been found in the first 440,000 people vaccinated against Covid-19 in Wales.
Scientists in Swansea University looked at anonymised patient data between January 1, 2019 and January 31, 2021 to determine whether there had been a rise in cases of venous sinus thromboembolism.
The extremely rare condition was found in a small number of patients in Norway and Germany and was one of the reasons why several European countries decided to temporarily halt the use of the Oxford AstraZeneca vaccine.
However the Medicines and Healthcare products Regulatory Agency (MHRA) said there has been no confirmation the reports of blood clots were caused by the vaccine.
In the 25-month period analysed by the Secure Anonymised Information Linkage (Sail) databank in Swansea University, a total of 19 cases of the disorder were recorded in Welsh patients, but no new cases were recorded in individuals who had received a vaccine in this period. Seven people with a previous diagnosis of this condition had been vaccinated by January 31, 2021.
Between December 4, 2020 and January 31, 2021, 440,000 people had at least one dose of the vaccine as recorded in the Welsh Covid-19 Vaccine data. Of these, 180,000 people received the Oxford AstraZeneca vaccine and 260,000 received the Pfizer Vaccine.
Ronan Lyons, professor of public health and director of Sail Databank said: "This is an important finding about the safety of the vaccines in use in Wales. We found no cases of this rare clotting disorder amongst the first 440,000 people who were vaccinated up until the end of January.
"We will continue to interrogate more data as it becomes available and as more people are vaccinated. This is very good news for our collective efforts to emerge from this pandemic and save more lives through the vaccination programme."
Venous sinus thromboembolism is a condition found in fewer than one person per month in the Welsh population of 3.2 million people.
As it is diagnosed in hospital, there is a delay in detailed coding of records which is why the analysis was completed up until end of January 2021 - but it will be updated going forward.
