Long-awaited results from AstraZeneca Plc's 30,000-person US Covid-19 vaccine trial are currently being reviewed by independent monitors to determine whether the shot is safe and effective, a top US official said on Monday.
If the data are positive and all goes well, said Dr Francis Collins, director of the National Institutes of Health, the US Food and Drug Administration could complete its reviews and issue an emergency use authorization in about a month, adding one more vaccine to the US arsenal.
The AstraZeneca vaccine, developed with the University of Oxford, has been authorized for use in the European Union and many countries but not yet by US regulators.
Several EU countries have halted administering the AstraZeneca vaccine after reports from Denmark and Norway of possible serious side-effects, including bleeding and blood clots.
Asked about those issues, Collins said he has not personally seen the data but has been "pretty reassured" by statements by European regulators that the problems could be occurring by chance, and are not related to the vaccine.
A World Health Organization expert advisory committee is currently looking into the matter.