Revelations of poor practices at a contract research company helping to carry out Pfizer’s pivotal covid-19 vaccine trial raise questions about data integrity and regulatory oversight. Paul D Thacker reportsIn autumn 2020 Pfizer’s chairman and chief executive, Albert Bourla, released an open letter to the billions of people around the world who were investing their hopes in a safe and effective covid-19 vaccine to end the pandemic. “As I’ve said before, we are operating at the speed of science,†Bourla wrote, explaining to the public when they could expect a Pfizer vaccine to be authorised in the United States.1But, for researchers who were testing Pfizer’s vaccine at several sites in Texas during that autumn, speed may have come at the cost of data integrity and patient safety. A regional director who was employed at the research organisation Ventavia Research Group has told The BMJ that the company falsified data, unblinded patients, employed inadequately trained vaccinators, and was slow to follow up on adverse events reported in Pfizer’s pivotal phase III trial. Staff who conducted quality control checks were overwhelmed by the volume of problems they were finding. After repeatedly notifying Ventavia of these problems, the regional director, Brook Jackson, emailed a complaint to the US Food and Drug Administration (FDA). Ventavia fired her later the same day. Jackson has provided The BMJ with dozens of internal company documents, photos, audio recordings, and emails.