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 we...