President Joe Biden announced Tuesday that his administration is working with coronavirus vaccine makers to buy another 200 million doses that would arrive this summer -- raising the total to 600 million and ensuring the U.S. will eventually have two shots of the Pfizer and Moderna vaccines for nearly every American.
Biden also said the federal government will be increasing the number of doses shipped to states -- from 8.6 million doses a week to 10 million a week for the next three weeks, and will start notifying states how many doses they will receive three weeks in advance.
"We will both increase the supply in the short term by more than 15%, and give our states and local partners more certainty about when the deliveries will arrive. These two steps are going to help increase our prospects of hitting or exceeding -- God willing -- the ambitious goal of 100 million shots in 100 days," Biden said in remarks at the White House on Tuesday.
But Biden said that "God willing" it will allow millions more people to be vaccinated earlier than anticipated, cautioning that the "brutal truth" is it will still take months to get through the majority of the population.
"This is going to allow millions of more Americans to get vaccinated sooner than previously anticipated. We've got a long way to go, though," he said.
The slight uptick to 10 million in the next three weeks had been expected, as vaccine makers slowly expand supply, and the U.S. government already had the option to buy more doses under existing contracts.
Under President Donald Trump, the U.S. government had already agreed to buy 200 million doses from Pfizer and 200 million from Moderna, which were delivered by July.
Because each vaccine requires two shots, those 400 million doses already purchased from Pfizer and Moderna would be enough to vaccinate about 200 million U.S. adults. But tens of millions more people will need to be immunized to reach "herd immunity."
Biden emphasized that the U.S. now expects 600 million doses of the two vaccines, enough for 300 million Americans to be fully vaccinated with both doses.
The FDA has not signed off on giving either of the available COVID-19 vaccines to children until the companies complete more research. The Pfizer vaccine is authorized in people as young as 16, whereas the Moderna vaccine is authorized for people over 18 years old.
A senior administration official did not provide a firm timetable on the 200 million extra doses, but hailed the move as a guarantee that every American who wants a shot can get one.
The official said using the Defense Production Act to boost supply remains an option. Examples include more specialized syringes and raw materials, although vaccine makers said there is little that can be done in the near term to boost supply rapidly because it is so highly technical.
"We will do everything in our power to increase the supply and speed the administration of the vaccine," the official said.
And in a moment that showed a significant contrast to his predecessor Biden also said that masks are the best way to defend against the virus in the coming months, saying not wearing a mask is "not very American."
"In the next few months, masks -- not vaccines -- are the best defense against COVID-19. Experts say that wearing masks from now just until April would save 50,000 lives who otherwise will pass away if we don't wear these masks. That's why I'm asking the American people to mask up for the first 100 days," he said.
He added "the fact is, you want to be patriotic, you're going to protect people."
This report was featured in the Wednesday, Jan. 27, 2020, episode of “Start Here,” ABC News’ daily news podcast.
"Start Here" offers a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, Spotify, the ABC News app or wherever you get your podcasts.