Intended for healthcare professionals


Covid-19: Researchers face wait for patient level data from Pfizer and Moderna vaccine trials

BMJ 2022; 378 doi: (Published 12 July 2022) Cite this as: BMJ 2022;378:o1731
  1. Jennifer Block
  1. New York

Independent researchers looking to obtain patient level data from the Pfizer and Moderna covid-19 vaccine trials may have to wait longer. In status reports filed recently with the US federal trials registry ( between February and May, both companies extended the dates by which the trials will be completed, Pfizer by nine months, from 15 May 2023 to 8 February 2024. Moderna’s expected completion date is delayed from 27 October to 29 December 2022.

Pfizer indicated in its trial protocol that individual participant data would be made available two years after study completion.1 Now that the date has been pushed back, Pfizer will entertain and review requests “when the study is complete and all planned analyses have been performed,” said the company’s senior director of global media relations, Jerica Pitts.

Luis Carlos Saiz, a researcher at the Innovation and Organisation Unit of the Navarre Regional Health Service, Spain, said that access to raw patient data was important for researchers because “it is key to build trust in health policies and to protect citizens from potential vested interests.”

The raw patient data would allow independent researchers to assess trials and verify results. “The vaccination strategies adopted by health authorities all over the world must be audited and checked by looking carefully at the raw data,” said Saiz, especially given the “revelations of poor practices” at vaccine trial sites as reported by The BMJ.2

Pitts explained by email that the completion date needed to be changed because of a single study participant “who received their second vaccination very late,” in the spring of 2022. “Given that the timing of downstream visits are dependent upon completion of the initial two doses, this pushed the overall primary completion date for the study out,” Pitts wrote. The total enrolment is 44 000 participants.3

Reformulating booster shots

In June the US Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee recommended that manufacturers reformulate booster shots to target omicron variants as well as the original strain.

Dick Bijl, president of the International Society of Drug Bulletins, is among the researchers who cite uncertainties about whether the products will be effective enough to warrant additional doses and whether the benefit will outweigh the risk of potential side effects—and how that risk-benefit ratio will differ among subgroups. “The main problem is that we need all the data,” he said. “The public needs transparent, open study details so they can judge for themselves whether they want to vaccinate or not.”

Bijl cited a recent preprint study that examined the first four months of Pfizer and Moderna trial data—the same dataset that was the basis for FDA emergency use authorisation—and found an excess risk of serious adverse events of 12.5 per 10 000.4 The authors pointed to the need for more formal analysis: “Individual participant data for all serious adverse events is not publicly available at present, but would help identify factors (e.g. age and comorbidities) that may elevate the risk.”

Bijl and Saiz are among hundreds of physicians and researchers who’ve joined the non-profit organisation Public Health and Medical Professionals for Transparency, which is suing the FDA to make Pfizer’s covid-19 vaccine biological product file data public and has already prompted some data to be released through the Freedom of Information Act, which the organisation is publishing on its website.5

Over the past decade researchers have pushed regulators successfully for more data transparency, achieving policy victories within the European Medicines Agency and Health Canada. In a May 2020 letter, researchers from the Institute for Quality and Efficiency in Health Care and Cochrane urged the EMA to publish detailed clinical study reports on all covid-19 drugs and vaccines in spite of accelerated authorisation,6 which they have done. But neither the EMA nor Health Canada holds participant level datasets; only the FDA and the sponsors do. “To assess these products further and to accelerate the development of additional products, the fast and full public availability of the information submitted to regulators is of utmost importance. Transparency is also vital to maintain public trust during the crisis,” said the letter.

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