President Joe Biden announced on Tuesday that the United States has now secured enough vaccine doses for every adult in the country to be fully vaccinated by the end of May.

"Three weeks ago, I announced we would have enough vaccine supply for all Americans by the end of July. Now, with our efforts to ramp up production, we will have enough vaccines for every American by the end of May," Biden tweeted.

In order to meet this accelerated goal, the White House announced on Tuesday that the pharmaceutical giant Merck (MRK  ) will aim rival Johnson & Johnson (JNJ  ) in production of the latter's one-dose coronavirus vaccine, which has been met with delays.

"Among the things that I learned when I came into office was the Johnson & Johnson was behind in manufacturing and production," Biden stated during a White House press conference announcing the production partnership. "While we had the potential of another highly effective vaccine to accompany the two existing ones, it simply wasn't coming fast enough. So my team has been hard at work to accelerate that effort."

Janssen Pharmaceuticals, part of Johnson & Johnson, has run into two production issues that have delayed the manufacturing of its coronavirus vaccine: slow manufacturing of the vaccine drug substance and problems with its fill-finish capacity, which is putting the drug into its distribution vials.

Under the drugmaker's contract with the U.S., Janssen was expected to deliver 12 million doses of the vaccine by the end of February. However, the company was only able to produce 3.9 million doses for shipment this week following its emergency use authorization on Saturday, and does not plan to deliver any vaccines next week.

At its current manufacturing capacity, Janssen expects to deliver 16 million doses by the end of the month. The company is contracted to deliver 100 million doses to the U.S. throughout 2021 through the Trump administration's Operation Warp Speed, which Jassen plans to reach by the end of June.

The new partnership between Merck and Janssen, alongside other efforts the federal government is taking under the Defense Production Act to accelerate the vaccine's production, will help the company deliver its target of 100 million doses by the end of May, according to the U.S. Department of Health and Human Services.

Additionally, the Biden administration will provide Merck with an initial investment of $105 million to upgrade its facilities in order to safely manufacture the vaccine, as well as expedite materials for vaccine production to the company and directed the Department of Defense to provide daily logistical support. President Biden has also called on Janssen's current manufacturing facilities to increase production to 24 hours a day, 7 days a week, with the government's help.

An increase in supply of the one-shot Johnson & Johnson vaccine sooner than previously expected would speed up the nation's vaccination effort enormously, because this vaccine allows twice as many people to be inoculated with the same number of shots produced by Pfizer (PFE  )-BioNTech (BNTX  ) and Mondera (MRNA  ). Both mRNA vaccines currently in circulation require two doses given a few weeks apart.

"One of my first goals in office was to say that there will be 100 million vaccination shots administered in my first 100 days," Biden stated. " We've got halfway to that goal in 37 days, and I feel confident we'll make it all the way."

Just over 26 million Americans have received both doses of a coronavirus vaccine to date, according to data from the U.S. Centers for Disease Control and Prevention. That is about 8% of the nation's population.