WASHINGTON—President Joe Biden urged states to pause reopening efforts and a top health official warned of “impending doom” on Monday, amid a surge in COVID-19 cases. Biden said 90 percent of adults would be eligible for vaccination by April 19, and 90 percent of Americans would have a vaccination center within five miles of their homes by then, as his team ramps up its drive to get vaccine shots in people’s arms. But the administration issued a stark warning: cases are rising, hospitalizations are increasing, and deaths are multiplying from the disease that has already killed roughly 550,000 people in the United States. “I’m reiterating my call for every governor, mayor and local leader to maintain and reinstate the mask mandate,” Biden said. “We still are in a war with this deadly virus. And we’re bolstering our defenses, but this war’s far from won.” Asked if states should pause re-opening …