Freedom of Information request on the batch numbers that appear most often in the adverse reactions reported following an AstraZeneca COVID-19 vaccine (FOI 22/762)
Published 21 December 2023
© Crown copyright 2023
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/freedom-of-information-responses-from-the-mhra-week-commencing-4-july-2022/freedom-of-information-request-on-the-batch-numbers-that-appear-most-often-in-the-adverse-reactions-reported-following-an-astrazeneca-covid-19-vaccine
FOI 22/762
6th July 2022
Dear
Thank you for your email dated 10 June 2022, where you requested further details of the top 50 batch numbers that appear most often in the Adverse Drug Reaction (ADR) reports, reported to the Yellow Card scheme in association with the COVID-19 AstraZeneca vaccine.
The MHRA continuously monitors the safety of vaccines through a variety of pharmacovigilance processes including the Yellow Card scheme. As part of our signal detection processes all adverse reaction reports received by the Yellow Card scheme are assessed and cumulative information reviewed at regular intervals. Vaccines encompass a wide variety of products with different indications, different ingredients and different mechanisms of action and as such safety for each vaccine is considered individually rather than as a group.
As per your request, a search has been conducted within our database for the total number of UK spontaneous suspected Yellow Card reports, for the top 50 most reported batch numbers for the COVID-19 AstraZeneca vaccine.
The requested information can be found in the enclosed attachment under Table 1. The table contains information on the top 50 most commonly reported batch numbers within all UK spontaneous suspected Adverse Drug Reaction (ADR) reports for the COVID-19 AstraZeneca vaccine received through the Yellow Card scheme for the time period up to and including 28/06/2022.
When considering this data it is important to note that it is not mandatory to provide batch numbers when submitting an adverse reaction report for a medicine or vaccine, and therefore the number of reports provided may not be a true reflection of the number of Yellow Card COVID-19 vaccine reports submitted for the respective batches.
In addition, not all batches of the COVID-19 vaccines are the same size and some batches may have had more wastage than other batches or be distributed more widely outside of the UK. Therefore, we would not expect the number of ADR reports for all batches to be the same as they have been administered to different numbers of patients.
Furthermore, different batches would have been used at different stages of the vaccination campaign, and in different patient groups, which could also impact reporting rates. For example, reporting rates were typically higher at the beginning of the vaccination campaign as individuals received their first dose and the likelihood of experiencing a reaction, as well as the propensity to report it, differs across patients of different ages. Please note that our analysis of these reports, which takes into account product batch number, did not result in any safety concerns, and therefore the provided data cannot be used to infer any safety concerns. Please be assured that the MHRA reviews this data regularly and we would communicate any concerns raised with the public and healthcare professionals. If you would like further information on batch usage, please contact the UK Health Security Agency (UKHSA) who hold this information.
When considering the attached spontaneous ADR data, it is important to be additionally aware of the following points:
-
A reported reaction does not necessarily mean it has been caused by the vaccine, only that the reporter had a suspicion it may have. The fact that symptoms occur after use of a vaccine, and are reported via the Yellow Card Scheme, does not in itself mean that they are proven to have been caused by the vaccine. 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. ADR reporting rates are influenced by the seriousness of ADRs, their ease of recognition, the extent of use of a particular drug, and may be stimulated by promotion and publicity about a drug.
As these data do not necessarily refer to proven side effects, you should refer to the product information which can be found here: Product Information - Coronavirus (COVID-19) (mhra.gov.uk) for details on the possible side effects of each vaccine.
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 relating to the COVID-19 vaccines is published each week and 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.
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