WASHINGTON (AP) — President Joe Biden says the U.S. expects to take delivery of enough coronavirus vaccines for all adult Americans by the end of May, two months earlier than anticipated, as his administration announced that drugmaker Merck & Co. will help produce rival Johnson & Johnson's newly approved shot. The announcement comes as the White House looks to speed the production of the single-dose J&J vaccine and accelerate the nation's plans to reach "herd immunity" in the U.S. and begin restoring normalcy after the pandemic. Biden also says he will be using the powers of the federal government to direct all states to prioritize vaccinating teachers.