The coronavirus vaccine from Pfizer could receive emergency use authorisation in weeks after the firm and its partner BIONTEC said they will be seeking US approval on Friday.
The vaccine which is due to arrive in the UK before the end of the year – is 95% effective and has passed its safety checks, according to further data from the firm.
The pharmaceutical giants published interim results last week showing the jab could prevent more than 90% of people developing Covid-19.
That data were based on the first 94 volunteers to develop Covid-19, but further figures released on Wednesday are based on the first 170 cases of the virus in the clinical trial.
The vaccine has been tested on 43,500 people in six countries and no safety concerns have been raised.
The UK has secured 40m doses in total of the vaccine, with 10m due in the country by the end of the year if it is approved.
People will need two doses, meaning enough vaccine has only been secured for 20m Brits.
Another jab, from US firm Moderna, was shown this week in early data to be almost 95% effective.
The UK has ordered five million doses of that jab, enough for 2.5m people, and is keenly awaiting the results of the Oxford University and AstraZeneca vaccine study – which is due to report soon. The U.K government has ordered 100m doses of that vaccine.
