US regulators have confirmed the Pfizer/BioNTech Covid vaccine is 95% effective, paving the way for it to be approved for emergency use.
The Food and Drug Administration (FDA) found no safety concerns to stop approval of the vaccine.
It is the first time this level of detail for the jab, which the UK has already started using for mass vaccination, has been published.
The FDA will meet on Thursday to make a formal decision.
The agency is yet to approve the vaccine, but has published a document stating the trial data was "consistent" with the recommendations set out in its emergency use guidance.
The UK's regulatory body, the MHRA, approved the vaccine last week.