The coronavirus vaccine being developed by Pfizer and BioNTech has been proved 95% effective overall, with efficacy in adults over 65 years of age at 94%, the companies said on Wednesday.
The US and German pharmaceuticals organisations said the candidate now met the safety criteria needed for emergency authorisation.
They plan to submit the vaccine to the US regulators for emergency use approval, the Food and Drug Administration (FDA), "within days".
The companies expect to produce globally up to 50 million vaccine doses in 2020 and up to 1.3 billion doses by the end of 2021.
"Pfizer is confident in its vast experience, expertise and existing cold-chain infrastructure to distribute the vaccine around the world," it said.
Primary efficacy analysis demonstrates BNT162b2 to be 95% effective against COVID-19 beginning 28 days after the first dose
Of the participants involved in the primary efficacy analysis, 95% were protected from the virus within 28 days of the first dose of the vaccine — this figure is up from the 90% announced by Pfizer from the results of Phase 3 trials.
Among over 43,000 participants enrolled in the tests, the companies said the vaccine was "well tolerated across all populations" with "no serious safety concerns observed".
They said 3.8% of people experienced fatigue and 2% headaches.
It came after US biotech company Moderna said on Monday that, based on preliminary data, their potential COVID-19 vaccine had been deemed to be 94.5% effective at preventing people from getting the virus.
Ursula von der Leyen, the president of the EU Commission, said the EU would sign a deal to secure up to 300 million doses of the BioNTech and Pfizer vaccine after “working tirelessly to secure doses of potential vaccines” in recent months.
The EU has agreed to a preliminary 160 million doses of the Moderna vaccine in its exploratory talks with the company, which could be finalised soon, a spokesman for the health commissioner said on Tuesday.
"In the context of the finalisation of the exploratory talks we agreed on 160 million doses," spokesman Stefan De Keersmaecker said at the European Commission's daily press conference. This would be 80 million doses plus an option to request an additional 80 million additional doses.
"Of course we continue to have negotiations, and we will see how this will be translated into an actual contract," he added.