It took the United States just 17 days to move from four million to five million coronavirus cases -- even as the country is finally starting to bend its curve downward.
Here is the state of play of America's Covid-19 epidemic, and what may happen in the coming months.
First some positive trends: the national daily new case rate has been falling for more than two weeks.
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The US is still recording more than 50,000 cases a day, a huge figure, but that's down substantially from 70,000 at the peak around July 23-24.
The drop-off in cases is so far more pronounced than in April when the country headed into a long springtime plateau, which lulled many states into a false sense of security that paved the way for the spike that began mid-June.
Experts attribute the decline to policy and behaviour changes in the populous states behind the summer surge -- namely California, Texas, Florida and Arizona.
Widespread adoption of masks, physical distancing and closing down bars all helped, while some scientists believe that increasing population immunity may have also played a role.
According to covid19-projections.com, up to 20 percent of Florida may by now have been infected -- and infection is thought to confer immunity to some extent.
"I believe the substantial epidemics in Arizona, Florida and Texas will leave enough immunity to assist in keeping Covid-19 controlled," Trevor Bedford, a scientist studying viruses at Fred Hutch wrote on Twitter.
"However, this level of immunity is not compatible with a full return to societal behavior as existed before the pandemic," he added.
Even if the trend is downward the daily case rate is still extremely high, and much more work needs to be done to bring the national curve back to baseline.
Unless the curve is pushed down much further, hospitals will continue to be stretched and people will continue to die needlessly. The current daily average is more than 1,000 deaths a day.
More than 163,000 have died so far -- 22 percent of the world's total, though the US has just four percent of the world's population.
Models predict 200,000 deaths by the middle of September.
And experts can already see the next area of failure emerging: cheered on by the administration of President Donald Trump, some states are rushing headlong to reopen schools in virus hotspots.
"We've seen the failure of federal leadership in the early days around PPE, we're seeing it over and over again around testing, and now we're seeing it around education policy," Thomas Tsai, a Harvard health expert told AFP.
A Georgia high school that suspended students for posting pictures of crowded hallways full of unmasked teens reported nine cases over the weekend, forcing the school to close down.
While children aren't at as great a risk as adults to getting severe Covid-19, cases are climbing.
A new report from the American Academy of Pediatrics and the Children's Hospital Association found that nearly 100,000 children were infected in the final two weeks of July, of a total of some 340,000 pediatric cases.
A recent study found children have higher viral load in their noses than adults, meaning they could be major spreaders once infected.
What comes next?
The reasons for the summer surge are clear and have been repeatedly articulated by experts: states that weren't initially hard hit got complacent and relaxed their lockdowns too soon.
They were supported by President Trump, whose administration also crucially failed to develop a national testing strategy unlike other developed countries.
It isn't rocket science: California, Texas, Arizona and Florida brought down their caseloads largely by implementing basic public health measures.
The key question to watch out for is whether other states will be proactive or simply wait until they experience their own surges before acting.
"When you have something that needs everybody pulling at the same time, if you have one weak link in there that doesn't do it, it doesn't allow you to get to the end game," Anthony Fauci, the country's top infectious disease official said Friday.
For his part, Trump seems to be betting everything on the emergence of an effective vaccine to end the crisis and win him re-election in November. The US has spent at least $9 billion so far on this goal.