Results from AstraZeneca’s recent Covid-19 vaccine trial “may have included outdated information” that “provided an incomplete view of the efficacy data,” a federal health institute said early Tuesday.

The National Institute of Allergy and Infectious Diseases issued the unusual statement after AstraZeneca announced Monday that the trial showed no serious side-effects, and that its vaccine was 100 percent effective in stopping severe and fatal cases.

The NIAID said that it had been notified late Monday about the “concern” by the the data and safety monitoring board, a panel of independent experts that reviews safety and efficacy data for vaccines in the United States.

March 22, 202102:08

“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,” it said, using the acronym for the data and safety monitoring board.

NBC News has reached out to AstraZeneca for comment.

The NIAID, which is part of the National Institutes of Health, did not suggest that the vaccine developed by AstraZeneca and Oxford University is unsafe or ineffective against the coronavirus. This shot has been taken by tens of millions of people around the world and approved by more than 50 countries.

The Phase 3 trial, whose results were released Monday, was conducted among 32,000 volunteers in the U.S., Chile and Peru. It was seen as the first step toward the vaccine getting approval in the U.S. perhaps as early as next month. It is unclear how the NIAID’s statement will impact this timeline.

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Despite posting strong results in clinical trials and real-world studies, this comes as the latest set back for the Oxford-AstraZeneca vaccine, in terms of public relations at least.

In the past two weeks, some European countries paused their rollouts after reports there had been extremely rare cases of blood clots among people who had taken it.

These countries resumed vaccinations days later after the European Medicines Agency, the continents’ top regulator, said there was no proven link between the vaccines and the clots.

But experts said the damage may have already been done: withholding a life-saving vaccine during a resurgent wave of the virus in Europe, while damaging public confidence in it.

European countries had previously said there was not enough data to approve the vaccine for people over the age of 65, before reversing that call too after studies suggested it was in fact very effective.


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