US President Joe Biden announced on Wednesday that his administration will order another 100 million doses of the Johnson & Johnson Covid-19 vaccine.
The planned purchase would bring the country's total vaccine order to 800 million doses.
"On Saturday, we hit a record of 2.9 million vaccinations in one day in America," Biden said.
Biden said last week the United States would have enough Covid-19 vaccine doses for every adult American by the end of May, which would dramatically accelerate his timeline previously set for the end of July.
There are three Covid-19 vaccines currently authorized for emergency use in the United States.
The US Food and Drug Administration authorized the one developed by American drugmaker Pfizer in partnership with German company BioNTech, and another by American drugmaker Moderna, in December last year.
Johnson & Johnson's Covid-19 vaccine was approved for emergency use on Feb 27. It is the first single-dose vaccine authorized in the United States.
Over 127 million vaccine doses have been distributed across the United States as of Wednesday, and more than 95 million doses have been administered, according to the US Centers for Disease Control and Prevention.
