FOI release
Endotoxin testing of BNT162b2 batch EJ0553 and validation of LAL testing
Case reference FOI2026/01386
Received 8 October 2026
Published 6 November 2026
Request
I want to raise a matter of concern regarding apparently inconsistent information provided in response to similar FOI requests I am aware you are under huge pressure to provide many answers to many people in time constraints. However I must draw your attention to a significant inconsistency in your public responses about the same subject matter. In FOI2024_00390 redacted for publication the question is As the MHRA informed the public on 2 December 2020 in the summary of the public asessment report, BioNTech's BNT162b2 mrna covid vaccine was manufactured 'through fermentation in an established and well-controlled Escherichia coli cell line, extracted and purified.' The purification method used by BioNTech to manufacture process 1 product which was used during the phase 1, 2 and 3 clinical trials was not scalable and could not be used to manufacture the mass manufactured process 2 product supplied to the UK under the December 2020 Regulation 174 authorisation. How did the MHRA establish that batch EJ-0553 and the other Regulation 174 batches were free of e-coli toxin (endotoxin) contamination in order to ensure that they were safe? If it was not free of e-coli endotoxin, on what scientific basis did the MHRA determine that the endotoxin was at a safe level? And who conducted the endotoxin testing of the Regulation 174 batches for the MHRA (eg was it the NIBSC or the manufacturer of the product? Please provide the endotoxin values as tested by the NIBSC for the following batches of BNT162b2 n Batch number 1NIBSC certificate issued on: 1 EJ0553 2.12.20 2 EJ0724 7.12.20 3 EJ1688 7.12.20 4 EL0141 7.12.20 5 EL0739 14.12.20 6 EK1768 17.12.20 7 EK4243 18.12.20 8 EK4237 21.12.20 9 EE8492 21.12.20 10 EE8493 21.12.20 Given the known risks of e-coli toxins, if no independent testing for e-coli endotoxin was commissioned by the MHRA for BNT162b2, please provide copies of any written policy statements or rationals explaining or justifying why such testing was deemed unnecessary. MHRA Response - Testing of batches of the Pfizer/BioNTech Covid-19 vaccine authorised under Regulation 174 was performed by the National Institute for Biological Standards and Control (NIBSC) to ensure that the batches were within specification limits defined during the assessment of this vaccine. The results of the tests performed by NIBSC are commercially sensitive and are, therefore, exempt from disclosure under Section 41 (information provided in confidence) and Section 43 (commercial interests) of the FOI Act. That implies very strongly that NIBSC tested Batch EJ0553 and the rest of bnT162b2 batches for endotoxin level. If so, that reply contradicts the interim rely sent to me. The further evidence of contradiction is the Batch release certificate also supplied . This shows the manufacturer not NIBSC performed the endotoxin active substance test. The certificate of release does not provide a result only a limit. The letter sent to me did not list the endotoxin test as an IBSC requirment. In order to clear up this matter, please confirm that NIBSC did not test the batch EJ0553 for endotoxin and only performed the five tests you state it ran in your reply to me. New supplementary question Please also provide evidence if held of confirmation that NIBSC/MHRA had in place a validation of the LAL testing method to detect masked endotoxin (l ow endotoxin recovery) in active substance chelated by EDTA added to the product. EDTA is referenced in the EMA EPAR. If not, was that validation requirement waived by the letter of no objection, responding to the Pfizer endotoxin test result provided to NIBSC in the redacted certificate for EJ0553
Response
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