AstraZeneca has said it has the capacity to manufacture one billion doses of the University of Oxford's potential COVID-19 vaccine and plans to begin supplying it in September.
The drugs giant also said it has already taken orders for at least 400 million doses of the coronavirus jab it is developing with the university.
It intends to negotiate further deals on capacity to "ensure the delivery of a globally accessible vaccine".
Results from an early stage clinical trial in southern England are expected shortly, it said.
If those are successful, other trials will follow in a number of countries.
Pascal Soriot, chief executive of AstraZeneca, said: "We need to defeat the virus together or it will continue to inflict huge personal suffering and leave long-lasting economic and social scars in every country around the world.