Update 4 pm EDT: The board of experts monitoring the clinical trial of AstraZeneca’s COVID-19 vaccine determined that the vaccine is actually between 69 percent and 74 percent effective at preventing symptomatic disease—not 79 percent effective, as AstraZeneca announced Monday.

According to a report by The Washington Post, the trial’s Data and Safety Monitoring Board (DSMB) had been in meetings with the company through February and March and saw data that indicated the 69-to-74 percent efficacy range. The board “strongly recommended” that the latest information be included in the company’s Monday press release.

However, the press release Monday only stated an efficacy of 79 percent and, in a second press release Tuesday, the company noted that they had used a data cut-off of February 17.

After the Monday press release, the DSMB sent AstraZeneca a highly unusual letter—which was viewed or obtained by The Washington Post—that heavily criticized the move.

“The DSMB is concerned that AstraZeneca chose to use data that was already outdated and potentially misleading in their press release,” the letter states. “The point that is clear to the board is that the [vaccine efficacy number]… they chose to release was the most favorable for the study as opposed to the most recent and most complete. Decisions like this are what erode public trust in the scientific process.”

Original story, 10:13 am EDT: A board of independent experts tasked with monitoring the data and safety of AstraZeneca’s COVID-19 vaccine trial has raised a red flag about the company’s Monday press release, which trumpeted that the vaccine was 79 percent effective at preventing symptomatic COVID-19.

In the wee hours of Tuesday, the National Institute of Allergy and Infectious Diseases released an unusual statement indicating that the trial’s Data and Safety Monitoring Board (DSMB) had been in touch with the federal agency as well as the company. The statement read:

The DSMB expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data. We urge the company to work with the DSMB to review the efficacy data and ensure the most accurate, up-to-date efficacy data be made public as quickly as possible.

In an interview with Good Morning America Tuesday morning, NIAID director and top infectious disease expert Anthony Fauci tried to add more context to the situation. He noted that the DSMB, which has access to all of the data from the AstraZeneca trial, was left surprised by what the company said in its press release.

“When [the DSMB] saw that press release, they got concerned and wrote a rather harsh note to them and copied to me,” Fauci said. “They felt that the data that was in the press release were somewhat outdated and might, in fact, be misleading.”

The unusual dispute is just the latest stumble for AstraZeneca’s COVID-19 vaccine, which has been plagued by doubts and disappointing results. Last week, more than a dozen countries in Europe and elsewhere temporarily paused the vaccine’s rollout over concern that it was causing life-threatening blood clots in a very small number of people.

Health experts, including the World Health Organization, urged countries to resume use of the vaccine, noting that benefits of protecting against COVID-19 greatly outweigh the risk of rare blood clots. Many countries have followed the advice and restarted vaccinations, but doubts linger about the vaccine. The new dispute over the data in the US press releases is likely to only add to the doubts.

“It really is unfortunate that this happened,” Fauci said this morning on GMA, calling the press release debacle an “unforced error” that would raise doubts further and may contribute to vaccine hesitancy. “The fact is, this is very likely a very good vaccine,” Fauci added. “If you look at the data they really are quite good, but when they put it into the press release it wasn’t completely accurate.”

In a press release early Tuesday, AstraZeneca addressed the controversy, apparently standing by its efficacy data for now:

The numbers published yesterday were based on a pre-specified interim analysis with a data cut-off of 17 February.

We have reviewed the preliminary assessment of the primary analysis and the results were consistent with the interim analysis. We are now completing the validation of the statistical analysis.

We will immediately engage with the independent data safety monitoring board (DSMB) to share our primary analysis with the most up to date efficacy data. We intend to issue results of the primary analysis within 48 hours.

https://arstechnica.com/?p=1751492