(Published 10 March 2021)
Cite this as: BMJ 2021;372:n627
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- Serena Tinari, journalist
Leaked documents show that some early commercial batches of Pfizer-BioNTech’s covid-19 vaccine had lower than expected levels of intact mRNA, prompting wider questions about how to assess this novel vaccine platform, writes Serena Tinari
As it conducted its analysis of the Pfizer-BioNTech covid-19 vaccine in December, the European Medicines Agency (EMA) was the victim of a cyberattack.1 More than 40 megabytes of classified information from the agency’s review were published on the dark web, and several journalists—including from The BMJ—and academics worldwide were sent copies of the leaks. They came from anonymous email accounts and most efforts to interact with the senders were unsuccessful. None of the senders revealed their identity, and the EMA says it is pursuing a criminal investigation.
The BMJ has reviewed the documents, which show that regulators had major concerns over unexpectedly low quantities of intact mRNA in batches of the vaccine developed for commercial production.
EMA scientists tasked with ensuring manufacturing quality—the chemistry, manufacturing, and control aspects of Pfizer’s submission to the EMA—worried about “truncated and modified mRNA species present in the finished product.” Among the many files leaked to The BMJ, an email dated 23 November by a high ranking EMA official outlined a raft of issues. In short, commercial manufacturing was not producing vaccines to the specifications expected, and regulators were unsure of the implications. EMA responded by filing two “major objections” with Pfizer, along with a host of other questions it wanted addressed.
The email identified “a significant difference in % RNA integrity/truncated species” between the clinical batches and proposed commercial batches—from around 78% to 55%. The root cause was unknown and the impact of this loss of RNA integrity on safety and efficacy of the vaccine was “yet to be defined,” the email said.
Ultimately, on 21 December, EMA authorised Pfizer-BioNTech’s vaccine. The agency’s public assessment report, a technical document published on its website, noted, “the quality of this medicinal product,