President Donald Trump has launched "Operation Warp Speed" in a bid to develop, manufacture and distribute a Covid-19 vaccine to all Americans by January 2021.
Hundreds of millions of dollars have been directed to vaccine developers including nearly $500 million to Johnson & Johnson at the end of March.
The United States has allocated funding to more companies than other nation in the hope that one of them will come up with the vaccine to counter the highly contagious virus.
So far, Washington has handed out at a total of least 9.4 billion dollars to seven vaccine developers and signed manufacturing contracts with five of them to provide 700 million doses.
The companies involved are: Johnson & Johnson, Moderna, Oxford/AztraZeneca, Novavax, Pfizer/BioNTech, Sanofi/GSK, Merck Sharp and Dohme.
Europe: 700 million doses
Two vaccine developers - Oxford/AztraZeneca and Sanofi/GSK - have signed or are in advanced negotiations with the European Commission to provide a combined 700 million vaccine doses.
Britain, Japan, Brazil
Britain, because of Brexit, is negotiating a separate pre-order of 250 million doses from four developers.
Japan is counting on 490 million doses from three suppliers including 250 million from Novavax of the United States.
Japanese pharmaceutical giant Takeda bought the rights to a Novavax vaccine for Japan, which has funded the research. It would be produced locally.
Brazil chose a similar model, ordering 100 million doses from AstraZeneca, and partnering with China's Sinovac to produce 120 millions of "CoronaVac," which is already undergoing testing with Brazilians.
Clinical tests of two Chinese vaccine candidates - Sinovac and Sinopharm - are well underway but only a few international partnerships have been announced, the one with Brazil and a possible one with Indonesia.
Russia said 20 nations have pre-ordered one billion doses of Sputnik V and that with foreign partners it would be able to produce 500 million doses a year in five countries.
The Coalition for Epidemic Preparedness Innovations (CEPI), launched in 2017 by Norway, India, the Bill and Melinda Gates Foundation and the Wellcome Trust, seeks to ensure that there is "equitable access" to future vaccines.
It has pre-ordered 300 million doses from AstraZeneca for dozens of developing countries in a partnership with The Vaccine Alliance (Gavi).
Billions of doses would be produced for Asia and elsewhere by the giant Serum Institute of India (SII), the largest vaccine producer in the world.
Novavax and AstraZeneca have separately signed agreements with SII to produce a billion doses each for India and low- and middle-income countries on the condition, of course, that they prove their efficacy in clinical trials.