WASHINGTON — The Biden administration launched its new level-with-America health briefings Wednesday with a projection that as many as 90,000 more in the U.S. will die from the coronavirus in the next four weeks — a sobering warning as the government strains to improve delivery and injection of vaccines. The tone of the hourlong briefing was in line with President Joe Biden’s promise to be straight with the nation about the state of the outbreak that has already claimed more than 425,000 U.S.