President Joe Biden announced Tuesday that the US will have enough vaccine supply for all adults by the end of May, two months earlier than previously expected.

Just weeks ago, the Biden administration said it expected to be able to inoculate every American adult by the end of July — but due to the collaboration between the two pharmaceutical giants and other actions, officials have been able to revise that forecast. Earlier on Tuesday, Merck & Co. agreed to help produce the Johnson & Johnson single-dose vaccine, a partnership Biden likened to efforts seen during World War II.