The data, as well as interviews across the country, show a far-reaching crisis. The worst-hit areas in Texas and Florida have approached the peak rates of hospitalization that New York, New Orleans, Chicago and other cities hit in the spring. A wide and growing expanse of hot spots around the country — including Las Vegas, Nashville and Tulsa, Okla. — have worsened over the past two weeks.

Not every hospital system is overwhelmed, and new treatments have improved the chances of survival for seriously ill people. But experts say a small but significant proportion of those currently hospitalized will die, and those who survive may face serious long-term health issues.

Months ago, the endless wail of ambulances in New York City conveyed the urgency of the virus outbreak in a concentrated area. Now, the scale of the crisis is dispersed and harder to grasp.

“There’s this pandemic fatigue,” said Thomas Tsai, an assistant professor of health policy at Harvard University. “All eyes were on New York. Houston is New York now. Miami is New York now. Phoenix is New York now. We need that shared collective urgency.”