Drugmaker AstraZeneca said it will release further data "within 48 hours" on US trials of its Covid-19 vaccine, after health officials raised concerns about the initial information disclosed.
The company pushed back against a statement from the US National Institute of Allergy and Infectious Diseases (NIAID) which said that "outdated information" may have been used to conclude that its vaccine was highly effective against Covid.
"We have reviewed the preliminary assessment of the primary analysis and the results were consistent with the interim analysis," AstraZeneca said in a statement.
"We intend to issue results of the primary analysis within 48 hours," it added.
The vaccine developed with Oxford University was 79% effective in preventing symptomatic illness in a large trial in the United States, Chile and Peru, and, crucially, posed no increased risk of blood clots, according to the data.
The Data Safety Monitoring Board (DSMB) has "expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data," NIAID
said in a statement.
NIAID director Dr Anthony Fauci said the AstraZeneca vaccine is likely very good, but an independent review board was concerned about how it presented data in the press release.
"This is likely a very good vaccine," Dr Fauci, who is also President Joe Biden's Covid-19 medical adviser, told ABC News.
"If you look at it, the data really are quite good but when they put it into the press release it wasn't completely accurate."
The DSMB "got concerned" that the data in AstraZeneca's public statement "were somewhat outdated and might in fact be misleading a bit," he added.
The board, a group of independent medical experts at the National Institutes of Health, which includes NIAID, contacted the company with their concerns about how the company laid out its data in its press release issued yesterday, Dr Fauci said.
He added that the back and forth was "unfortunate," calling it "an unforced error" that only adds to public doubts about vaccines and could possibly lead to more hesitancy.
The US Food and Drug Administration, which will review the company's data when it seeks approval for its vaccine in the United States, "will independently go over every bit of data themselves" and not rely on any one interpretation, including the company's, he added.
Hailed as a milestone in the fight against the Covid-19 pandemic when it emerged as a vaccine contender last year, the AstraZeneca shot has been dogged by doubts over its efficacy, dosing regimen and possible side effects.
More than a dozen European countries, including Ireland, Germany and France, halted use of the vaccine earlier this month after reports linked it to a rare blood clotting disorder in a very small number of people.
Ireland resumed administering the vaccine at the weekend.
The latest trial data, which have yet to be reviewed by independent researchers, was set to give credence to the vaccine after results from earlier, separate late-stage studies raised questions about the robustness of the data.
Dr Fauci said yesterday that the US trial found no indication at all of the rare blood clots.
The latest data was based on 141 infections among 32,449 participants.
The vaccine has also been at the centre of a growing conflict between the European Union and Britain over so-called vaccine nationalism after a string of supply setbacks in Europe.
