The coronavirus outbreak in the U.S. continues to slow, driven by significant progress in the South and Southwest, where cases skyrocketed earlier this summer.

Why it matters: All of the second-order controversies consuming the U.S. — like whether to open schools for in-person instruction — would be easier to resolve if we could get the virus under control and keep it there.

The big picture: The number of new infections in the U.S. fell by nearly 8% over the past week — the fourth straight week of nationwide improvement.

• Arizona and Florida, two of the biggest contributors to the explosion of new cases in June and July, recorded significant improvement this week. Cases were down 18% in Arizona and 25% in Florida.
• The other big summer hotspots, California and Texas, held steady, while the hard-hit South improved overall.

By the numbers: The U.S. averaged just under 49,000 new cases per day over the past week — still a lot of cases, and far too many to declare any sort of victory over the coronavirus, but an improvement from the 65,000 daily cases we were averaging in mid-July.

• Nationwide, testing held steady at roughly 722,000 tests per day.

Yes, but: New warning signs cropped up this week in Kentucky and a handful of Midwestern states.

• As we’ve already learned multiple times throughout this pandemic, once the virus gains a new foothold, it can become highly mobile very quickly.

Between the lines: Each week, Axios tracks the change in new coronavirus infections from the week before, using a seven-day average to minimize any day-to-day abnormalities in reporting.

• This map illustrates how each state has changed over a one-week period; it is not a static snapshot of the severity of each state’s outbreak.
• Maine looks bad on the map, but only because it jumped from 11 cases per day to 23.