Top scientists at the World Health Organization on Friday called for more detailed information on a coronavirus vaccine developed by AstraZeneca and the University of Oxford.

Why it matters: Oxford and AstraZeneca have said the vaccine was 90% effective in people who got a half dose followed by a full dose, and 62% effective in people who got two full doses. AstraZeneca has since acknowledged that the smaller dose received by some participants was the result of an error by a contractor, per the New York Times.

• The half-dose version — the one with 90% efficacy — was tested on a group that didn’t include anyone older than 55, leading to questions about reliability of the results.
• AstraZeneca CEO Pascal Soriot told Bloomberg on Thursday the company is likely to start a new global trial to measure how effective the vaccine is.

What they're saying: "What we've seen is a press release. And what is really the next most important step is that the data really needs to be evaluated based on more than a press release," Katherine O'Brien, director of WHO's immunization and vaccines department, said Friday when asked to comment on AstraZeneca's vaccine.

• "So I think it's too early for us to say anything about what we make of the data and what is needed next. What we really see is more than a press release and to really see the data and have a chance to ask the questions that are needed," O'Brien said.
• "We've heard from AstraZenecathat they would like to do a full trial," said Soumya Swaminathan, the WHO's chief scientist, after noting that all available information on the vaccine has so far come from a press release. "And so if we are to explore this hypothesis of having perhaps a better efficacy with a lower dose, then it would need a trial."

Go deeper: Why AstraZeneca's vaccine matters for the developing world