The Virus Surge, Once Centered in the Midwest, Is Accelerating in 45 U.S. States

AstraZeneca said its vaccine candidate was up to 90 percent effective, suggesting that the world could eventually have at least three working vaccines. At the same time, the virus is accelerating across the U.S., and officials are imposing new restrictions to flatten the curve. When infections began rising sharply in the U.S. in September, the growth was driven largely by outbreaks in the Upper Midwest. States like North Dakota and Wisconsin soon became the hardest hit in the nation, relative to their size, and the region continues to struggle. Now, though, with the whole country’s daily average of new cases is as high as it has ever been — over 171,000 — the most rapid growth is happening elsewhere.