Drugs giant AstraZeneca has announced it is ready to provide a potential new coronavirus vaccine from September.
The firm said it had concluded deals to deliver at least 400 million doses of the vaccine, which it is developing with Oxford University.
AstraZeneca said it was capable of producing one billion doses of the AZD1222 vaccine this year and next.
Initial trials are under way and AstraZeneca said it recognised that the vaccine might not work.
But the company said it was committed to advancing the clinical programme.
Scientists have warned that a coronavirus vaccine, if developed, might not confer full immunity, while Prime Minister Boris Johnson has warned that a vaccine might never be found.
Despite these reservations, intensive research continues, with about 80 groups around the world working on possible vaccines.
AstraZeneca indicated that production would take place in more than one country. It thanked the UK and US governments for "substantial support to accelerate the development and production of the vaccine".
It also said it was in discussions with the Serum Institute of India and other potential partners to increase production and distribution.
Specifically, it said it had received support of more than $1bn from the US Biomedical Advanced Research and Development Authority (BARDA) for the development, production and delivery of the vaccine,
AstraZeneca chief executive Pascal Soriot described the coronavirus pandemic as "a global tragedy" and "a challenge for all of humanity".
"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," he said.
"We are so proud to be collaborating with Oxford University to turn their ground-breaking work into a medicine that can be produced on a global scale."
The Anglo-Swedish company reported it had received more than $1 billion from the U.S. Biomedical Advanced Research and Development Authority for the development, production and delivery of the vaccine, starting this fall.
The investment will accelerate the development and production of the vaccine, Soriot said. It had already joined forces with the British government and is in discussions with the Serum Institute of India and other potential partners to increase production and distribution.
"We will do everything in our power to make this vaccine quickly and widely available,'' Soriot said.
Pharmaceutical companies including also Moderna and Sanofi are racing to develop and produce a vaccine against the new coronavirus as experts say it will be crucial to allowing countries to ease their lockdowns and restrictions on public life.
In a statement as markets opened, AstraZeneca said it has now secured manufacturing capacity for 1 billion doses and aims to secure further agreements to expand capacity further over the next months ``to ensure the delivery of a globally accessible vaccine.''
The company also finalized its licence agreement with Oxford University for the vaccine, now known as AZD1222.
The vaccine was developed by Oxford University's Jenner Institute, working with the Oxford Vaccine Group.
Testing of the experimental COVID-19 vaccine began in healthy volunteers in Britain in April with over 1,000 healthy volunteers aged 18 to 55.
Data from the trial is expected soon and if results are positive, further trials will take place in other countries..
``AstraZeneca recognizes that the vaccine may not work,'' the statement said, ``but is committed to progressing the clinical program with speed and scaling up manufacturing at risk.''
Experts like Lawrence Young, a professor of molecular oncology at the University of Warwick, said the development was important in planning for the equitable supply of the vaccine throughout the world. But he urged caution and said other vaccine candidates should be explored.
``It is ...jumping the gun as we don't know that this vaccine will work,'' he said. ``Early studies using the Oxford vaccine in monkeys showed that while vaccination reduced the severity of disease preventing pneumonia it failed to stop the animals from becoming infected,'' with the virus that causes COVID-19.