The chief adviser for the US government’s Operation Warp Speed coronavirus vaccine programme, Moncef Slaoui, on Friday said that the administration hopes to immunise about 20 million citizens in December and a minimum of 25 million each month next year, The Politico reported.

Speaking at an event in the White House, Slaoui said that two vaccines in the final phase of trials developed by Pfizer and Moderna would soon be approved for emergency use in a matter of weeks by the Food and Drug Administration.

Slaoui said that there could be more authorised vaccines by 2021, increasing chances for more Americans to get immunised. “As of the month of February or March, if we have more vaccines approved...we may be able to immunise a larger number of Americans on an ongoing basis per month,” he added.

Gustave F Perna, Operation Warp Speed’s chief operating officer, said that the US government would begin vaccination within 24 hours after a shot secures emergency authorisation.

United States is the country worst-affected by the coronavirus in the world. The country, with about 4% of the world’s population, represents almost a fifth of all reported cases. It has recorded more than 1,07,45,520 cases and over 2,44,360 deaths since the pandemic started, according to Johns Hopkins University’s data.

On Monday, the drug maker Pfizer and German biotechnology company BioNTech announced that their experimental coronavirus vaccine is more than 90% effective based on initial trial results. Pfizer plans to ask the Food and Drug Administration for emergency authorisation of the two-dose vaccine later this month, reports said.

Eleven vaccines are in late-stage trials, including four in the US, according to The New York Times. Moderna, another front-runner in the global race to produce a vaccine to fight the infection, has said that it expects interim findings from its study this month. Russia’s sovereign wealth fund published interim late-stage trial results for its Sputnik V vaccine on Wednesday, showing the shot is 92% effective at protecting people from the coronavirus.