Freedom of Information request on whether having Hashimotos Thyroiditis is a a blood clot risk factor with COVID-19 vaccine (FOI 21/456)
Published 28 June 2021
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24th May 2021 FOI 21/456 Dear
Thank you for your Freedom of Information (FOI) request where you asked the following:
Please can you let me know if anyone is looking into whether having Hashimotos Thyroiditis is a risk factor for having a blood clot with low platelets following the first or second dose of the Astrazenca Covid vaccine? I am wondering how many of the people who have had such clots also had Hashimotos Thyroiditis?
The MHRA has undertaken a thorough review into UK reports of an extremely rare specific type of blood clot in the brain, known as cerebral venous sinus thrombosis (CVST) occurring together with low levels of platelets (thrombocytopenia) following vaccination with the COVID-19 Vaccine AstraZeneca. It is also considering other blood clotting cases (thromboembolic events) alongside low platelet levels. This ongoing scientific review has concluded that the evidence of a link with COVID-19 Vaccine AstraZeneca is stronger and an announcement was made on 7 April 2021 with a further statement on 7 May. We have continued to publish the latest breakdown of all cases of these extremely rare side effects on a weekly basis (please see https://www.gov.uk/government/publications/coronavirus-covid19-vaccine-adverse-reactions).
Information for healthcare professionals and information for the public about the COVID-19 Vaccine AstraZeneca, including information on the extremely rare cases of blood clots with low levels of platelets observed following vaccination with COVID-19 Vaccine AstraZeneca, is available at: https://www.gov.uk/government/publications/regulatory-approval-of-covid-19-vaccine-astrazeneca. As outlined in section 4.4. ‘Special warnings and precautions for use’ of the information for healthcare professionals, risk factors for thromboembolic events with concurrent thrombocytopenia have not been identified.
As of 12th May 2021, the MHRA has not received any cases of blood clotting alongside low platelet levels in which it was reported that the patient had Hashimotos thyroiditis.
I hope the information provided is helpful, but if you are dissatisfied with the handling of your request, you have the right to ask for an internal review. Internal review requests should be submitted within two months of the date of this response; and can be addressed to this email address.
Yours sincerely, FOI Team, Vigilance and Risk Management of Medicines Division