FOI release

Freedom of Information request about he number of people who post COVID infection developed a thrombus events (FOI-21-277)

Published 28 May 2021

Thank you for your email dated 18th March 2021 where you requested statistics regarding the number of people who post COVID infection developed a thrombus events and whether those who have had post vaccination thrombotic events been tested for previous or concurrent COVID infection.

The Medicines and Healthcare products Regulatory Agency (MHRA) is the executive Agency of the Department of Health and Social Care that acts to protect and promote public health and patient safety, by ensuring that medicines and medical devices meet appropriate standards of safety, quality and efficacy.

The MHRA operates the Yellow Card scheme on behalf of the Commission on Human Medicines (CHM). The scheme collects and monitors information on suspected safety concerns or incidents involving vaccines, medicines, medical devices, and e-cigarettes. The scheme relies on voluntary reporting of suspected adverse incidents by healthcare professionals and members of the public (patients, users, or carers). The purpose of the scheme is to provide an early warning that the safety of a product may require further investigation. Further information about the Yellow Card scheme, including its contribution to identifying safety issues can be found on the Yellow Card website.

The MHRA does not collect information exclusively on COVID infections; this information is only asked for when a possible reaction to a COVID-19 vaccination is reported via the Yellow Card scheme. Further information on COVID infections can be found on the Daily Summary and you can request additional information from Public Health England (PHE). Regarding the information on COVID infection in relation to Yellow Card reports of thrombus, this information is not available across all reports; however, MHRA works across the healthcare system to considers the totality of the data in the case reports when evaluating the evidence.

The MHRA has played an active role in responding to the coronavirus pandemic. In relation to COVID19 vaccines, the MHRA has authorised their supply following a rigorous review of their safety, quality, and efficacy. The clinical trials of COVID-19 vaccines have shown them to be effective and acceptably safe; however, as part of its statutory functions, the MHRA is responsible for monitoring these vaccines on an ongoing basis to ensure their benefits continue to outweigh any risks. This is a requirement for all authorised medicines and vaccines in the UK. This monitoring strategy is continuous, proactive, and based on a wide range of information sources, with a dedicated team of scientists reviewing information daily to look for safety issues or unexpected rare events.

Regarding thrombotic events, the MHRA has undertaken a thorough review into UK reports of a very rare and unlikely to occur 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. The likelihood of these blood clots occurring is still extremely rare. As a precaution, administration of COVID-19 Vaccine AstraZeneca in people of any age who are at higher risk of blood clots because of their medical condition should be considered only if benefits from the protection from COVID-19 infection outweighs potential risks. The MHRA recently confirmed that the evidence to date does not suggest that the COVID-19 Vaccine AstraZeneca causes venous thromboembolism without a low platelet count. It is important to note that this type of blood clot together with lowered platelets can rarely occur naturally in unvaccinated people as well as in people with COVID-19 disease.

A weekly report on adverse reactions to approved COVID-19 vaccines can be found here; https://www.gov.uk/government/publications/coronavirus-covid-19-vaccine-adverse-reactions.

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