CDC data shows the U.S. "Turning the Corner" Fueling hope and relaxation

After weeks of coronavirus patients flooding emergency rooms in Michigan, the worst Covid-19 hot spot in the nation, hospitalizations are finally falling.

On some recent days, entire states, including Wisconsin and West Virginia, have reported zero new coronavirus deaths — a brief but promising respite from the onslaught of the past year.

And in New York and Chicago, officials encouraged by the recent progress have confidently vowed to fully reopen in the coming weeks, conjuring images of a vibrant summer of concerts, sporting events and packed restaurants revving cities back to life.

Americans have entered a new, hopeful phase of the pandemic. Buoyed by a sense that the coronavirus is waning, in part because of vaccinations, more people are shrugging off masks, venturing into restaurants and returning to their prepandemic routines. Mayors, governors and other local officials — once the bearers of grim news about the virus’s toll and strict rules for businesses — have joined in the newfound optimism, rapidly loosening restrictions.

Public health experts remain cautious, but said that while they still expect significant local and regional surges in the coming weeks, they do not think they will be as widespread or reach past peaks. ...

In the past, lulls in the pandemic were short-lived, giving way to the surge across the Sun Belt last summer, and the painful outbreak that stretched across the United States this winter.

But now, there is one crucial difference: More than half of American adults — 148 million people — have received at least one dose of a coronavirus vaccine, perhaps the biggest reason experts are optimistic that the improved outlook may last. Cases, hospitalizations and deaths have also fallen at a time when the weather is getting warmer, which, in many places, will allow people to spend more time outdoors, where the virus spreads less easily. ...

...  even as a sense of hope spreads, there remain strong reasons for caution. The pace of vaccinations is slowing, and experts now believe that herd immunity in the United States may not be attainable. More transmissible variants of the virus are also spreading, threatening to undermine the progress from vaccinations.

That could leave the coronavirus infecting tens of thousands of Americans and killing hundreds more each day for some time. A modeling study released by the Centers for Disease Control and Prevention on Wednesday, citing relaxed restrictions and a new, contagious variant, suggested that cases could tick upward again in the coming weeks, before a sharp drop-off by July. Dr. Rochelle Walensky, the director of the C.D.C., said, “We are not out of the woods yet, but we could be very close.” ...