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BSI response to announcement from MHRA and JCVI relating to the AstraZeneca/Oxford COVID vaccine & rare blood clots

7 April 2021

The Medicines and Healthcare products Regulatory Authority (MHRA) and the Joint Committee on Vaccination and Immunisation (JCVI) today held a joint press conference to provide an update on their investigations into the AstraZeneca/Oxford COVID-19 vaccine and rare cases of blood clots and low blood platelets.  You can read their full statements on their websites via the links above. In response to the announcements made during this press conference, the British Society for Immunology has released the following statement. 


 Professor Arne Akbar, President of the British Society for Immunology, said:

“As for all new vaccines and medications, the rollout of the new COVID-19 vaccines has been monitored extremely closely by the UK regulator, the Medicines and Healthcare products Regulatory Agency (MHRA).  Today’s update highlights the importance of having this active monitoring in place and the fact that the regulator, working with the Joint Committee on Vaccination and Immunisation (JCVI), has acted to issue updated information today shows that this monitoring system is working well.

“After careful analysis, the JCVI have issued new guidance concerning who should receive the AstraZeneca/Oxford COVID-19 vaccine. This will have been the result of dozens of experts who have many years of experience in this area carefully scrutinising the available data.  To be ultra cautious, they have advised that while the benefits of vaccination continue to outweigh the risks for everyone, people under 30 with no other health conditions should be offered an alternative vaccine to the AstraZeneca/Oxford vaccine where available.

“This is due to very rare reports of individuals developing blood clots with low platelet counts after receiving this vaccine.  While the evidence is still accumulating to allow us to say definitively whether these symptoms are linked to the vaccine or not, the JCVI is taking a careful, proactive approach in acting now. The reason for this shift in emphasis for younger people is because the benefit to risk ratio is less pronounced than in older people who are at higher risk of severe COVID-19 disease. We still don’t have a clear understanding of what the mechanism behind these potential side-effects could be. Although there is some early evidence that there is an adverse immune response occurring that affects the platelets, we urgently need more research to clarify this.

“I would like to reassure people that the occurrence of these blood clots linked to low platelet counts after having the AstraZeneca/Oxford vaccine appears to be extremely rare – around one in 250,000. Vaccines are still the best way to protect yourself from catching COVID-19, which has a far higher risk of serious health effects. If you receive the call to get your COVID vaccine, I would urge you to do so. If you have any questions about vaccination, please speak to your GP or healthcare professional.”


You can read the full statement from the MHRA here and the statement from the JCVI here