FOI release

Freedom of Information request on adverse reaction reports regarding blood clots following receiving one or more AstraZenece COVID-19 vaccination (FOI 22/798)

Published 4 January 2024

FOI 22/798

28th July 2022

Dear

Thank you for your email dated 4th July 2022, where you requested information on the following:

3) “For patients who have received one or more doses of the AstraZeneca COVID-19 vaccine, how many fatal cases of blood clots have been recorded in England to date, broken down for the following periods?

a) April 2020 to March 2021

b) April 2021 to March 2022

4) For patients who have received one or more doses of the AstraZeneca COVID-19 vaccine, how many non-fatal cases of blood clots have been recorded in England to date, again broken down for the following periods?

a) April 2020 to March 2021

b) April 2021 to March 2022”

You also requested additional information on the 19th July 2022 on the following:

“10) How many individuals who have received the AstraZeneca COVID-19 vaccine and have experienced a blood clot(s) are currently: a. In-patients receiving treatment in hospital or medical centre b. Outpatients who have or are still receiving professional medical support c. Outpatients who are not receiving ongoing professional medical support”

We first wish to highlight that the current evidence does not suggest that the COVID-19 Vaccine AstraZeneca increases the risk of venous thromboembolic events (i.e deep vein thrombosis /pulmonary embolism) that occur without an accompanying reduction in platelet count. There is evidence of a link between the COVID-19 Vaccine AstraZeneca and thromboembolic events with concurrent low platelets. Therefore, may we ask for clarification on the following points:

• Whether your enquiry solely relates to pulmonary embolism in association with COVID-19 Vaccine AstraZeneca, or if your enquiry relates to any thromboembolism

• Whether your enquiry relates to the risk of thromboembolism in the absence or presence of low platelet count

In response to Question 3 regarding fatal blood clots in recipients of the COVID-19 Vaccine AstraZeneca, we can provide information from reports received by the MHRA via the Yellow Card Scheme. The Yellow Card scheme is the UK system for collecting and monitoring information on suspected safety concerns or incidents involving medicines and medical devices, operated by the MHRA. We can confirm that 71 reports of venous thromboembolic events that reported a fatal outcome were received between 01/04/2020 and 31/03/2021, and 176 reports were received between 01/04/2021 and 31/03/2022.

In response to Question 4 regarding reports of non-fatal blood clots in recipients of the COVID-19 Vaccine AstraZeneca, we can confirm that 623 reports of venous thromboembolic events that did not report a fatal outcome were received between 01/04/2020 and 31/03/2021, and 2762 reports were received between 01/04/2021 and 31/03/2022.

In response to Question 10, the MHRA only holds information about the outcomes of a suspected event provided by the reporter at the time of submitting a Yellow Card report. Whilst we may receive follow up information from the reporter on the patient’s outcome for some individual cases, it is not mandatory for reporters to provide such updates. Therefore, reports will only hold outcome information provided at the point of reporting or follow-up, and not information about status at the current date. We are therefore not able to provide information about the current status of the patients in Questions 3 and 4.

When considering the above data it is important to note the following:

• The provided data includes reports received within the United Kingdom and is not restricted to England. This is because it is optional for reporters to provide information (such as postal code) that could be used to identify the country when submitting a Yellow Card report, and therefore this is unlikely to accurately reflect the number of reports received from England.

• Whilst the above reports included in response to Question 3 refer to fatal reports, this may not necessarily mean the patient died due to a blood clot specifically as the patient may have died due to other co-reported events.

• The provided data refers to any venous thromboembolic event (included on our system under the grouping “embolic and thrombotic events, venous”) and is not restricted to pulmonary embolisms.

• The provided data only includes Adverse Drug Reaction (ADR) reports reported to the MHRA, such as Yellow Card reports, and may not necessarily include reports received by other health authorities. The Yellow Card scheme operates on a mandatory basis for pharmaceutical companies however submitting an ADR report is optional for patients and healthcare professionals.

• A reported reaction does not necessarily mean it has been caused by the vaccine, only that the reporter had a suspicion it may have. Each year, millions of doses of vaccinations are given in the UK alone, and when any vaccine is administered to large numbers of people, some recipients will inevitably experience illness following vaccination. The fact that symptoms occur after use of a vaccine or medicine, and are reported via the Yellow Card Scheme, does not in itself mean that they are proven to have been caused by it. Underlying or concurrent illnesses may be responsible and such events can also be coincidental.

• It is also important to note that the number of reports received via the Yellow Card scheme does not directly equate to the number of people who suffer adverse reactions and therefore cannot be used to determine the incidence of a reaction or compare the safety profile of different vaccines. ADR reporting rates are influenced by the seriousness of ADRs, their ease of recognition, the extent of use of a particular medicine, and may be stimulated by awareness about a medicine or a suspected side effect. Reporting tends to be highest for newly introduced medicines during the first one to two years on the market and then falls over time.

The MHRA has been proactively monitoring the safety of all approved COVID-19 vaccines for near real-time safety monitoring at the population level. A summary of Yellow Card reporting concerning the COVID-19 vaccines can be found here. The summary includes data analysis on reported suspected adverse reactions from the COVID-19 vaccines, including those with a fatal outcome. A section on thromboembolic events with concurrent low platelets is also provided in the summary.

These cases of thromboembolic events with concurrent low platelets mentioned in the summary of Yellow Card reporting have also been analysed by the independent advisory body, the Commission on Human Medicines’ COVID-19 Vaccines Benefit Risk Expert Working Group, which includes lay representatives and advice from leading haematologists. On the basis of this ongoing review, the advice remains that the benefits of the vaccine outweigh the risks in the majority of people.

As mentioned above, the MHRA has confirmed that the evidence to date does not suggest that the COVID-19 Vaccine AstraZeneca increases the risk of venous thromboembolism (i.e. deep vein thrombosis/pulmonary embolism) in the absence of a low platelet count. The MHRA will continue to closely monitor reports of venous thromboembolism following COVID-19 vaccination.

As with any serious suspected ADR, reports with a fatal outcome are fully evaluated by the MHRA to consider whether the vaccine (or medicine) may have caused the event or whether the event and fatal outcome were likely to be purely coincidental and due to underlying illness.

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