In a highly unusual statement issued early this morning, United States health officials said that the data released by AstraZeneca on its COVID-19 vaccine may include “outdated information.” The announcement, which came from the National Institute of Allergy and Infectious Diseases (NIAID), comes less than a day after the pharmaceutical company said its vaccine was highly effective in the US trial.

The NIAID said that the independent board of experts reviewing data from the trial raised concerns about the publicly released data. It “may have provided an incomplete view of the efficacy data,” the agency said in its statement.

The announcement may contribute to some unnecessary hesitancy around the AstraZeneca vaccine, Anthony Fauci, director of the NIAID, said on Good Morning America this morning.

“This is really what you call an unforced error because the fact is, this is very likely a very good vaccine,” he said. “If you look at it the data, they really are quite good, but when they put it into the press release, it wasn’t completely accurate.”

AstraZeneca said in a statement that the information it released was based on data collected up until February 17th. The company said it is analyzing the most recent data now and will share it within 48 hours.

Typically, disagreements between companies and the independent boards overseeing their trials don’t happen in public, clinical trials expert Eric Topol told The New York Times. “I’ve never seen anything like this,” said Topol, who also directs the Scripps Research Translational Institute in California.

This morning’s announcement is the latest in a long line of issues with the AstraZeneca vaccine. The company hasn’t been as transparent with regulators as it should and gave some clinical trial participants in the United Kingdom the wrong dose of its vaccine. European doctors raised safety concerns after some people had unusual clotting disorders after receiving the vaccine. Experts hoped that yesterday’s announcement, which included data from the large and tightly controlled US clinical trial, would help clarify lingering questions about the vaccine and restore some confidence in the shot.

If and when AstraZeneca applies for authorization in the US, it will have to send all of the data from the US clinical trial to the Food and Drug Administration. Agency scientists will publish their independent analysis publicly, which will give experts the opportunity to review it as well.

The AstraZeneca COVID-19 vaccine is already being used in multiple countries around the world.