Information for patients about the Astra Zeneca COVID-19 vaccine

Clinical Commissioning Groups in Hertfordshire and West Essex have provided information for patients about the Astra Zeneca vaccine. You may be aware that some European countries have temporarily paused its use as a precautionary measure, following reports of blood clots in a small number of people who had recently had the vaccine.

Question: Does the Oxford Astra Zeneca vaccine cause blood clots?

Answer: Blood clots can occur naturally and are not uncommon. Reports of blood clots received so far are not greater than the number that we would normally expect to see amongst the groups of the population who have been vaccinated. People should still go and get their COVID-19 vaccine when asked to do so.

More than 11 million doses of the Astra Zeneca vaccine have now been administered across the UK. Vaccine safety is of paramount importance and the regulatory agency, the Medicines and Healthcare products Regulatory Agency (MHRA) continually monitors the safety of vaccines in the UK.

For more information and a statement from the MHRA, please visit

The above information, along with answers to other frequently asked questions about the vaccine roll-out, is available on the A Healthier Future COVID-19 website.