Nearly half of states reopened before meeting the White House safety criteria. Their new surges were entirely predictable.

• Nearly half of US states started reopening in late April and early May without meeting the White House guidelines, which suggested states first see downward trends in coronavirus cases or positive tests.
• The majority of those states are now seeing new cases jump — a consequence of loosening restrictions too early.

The US reported its highest-ever number of new coronavirus cases on Thursday: nearly 39,000.

The new surge in cases is more widespread geographically than the initial one, with nearly 30 states seeing daily coronavirus cases rise over the last two weeks.

"This is a continuation of the first wave," Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security, previously told Business Insider. "Some places that might have been relatively spared early on in the winter and the spring are now facing cases higher than they had before."

There's a reason for that: Many states started reopening their economies in late April and early May without meeting the White House criteria for resuming business operations and social activities. The guidelines said states should see either a two-week decline in cases or a two-week decline in the share of coronavirus tests coming back positive before they reopened.

But 21 states started reopening around May 7 without seeing those trends, according to the New York Times. The majority of those states have seen new coronavirus cases rise in recent weeks.

As of Thursday, all 50 states have reopened, but more than half do not currently meet the White House safety criteria, according to a ProPublica analysis. After factoring in states' hospital capacity, coronavirus-testing capacity, and antibody-testing programs for essential workers, only three states — Alaska, Connecticut, and Illinois — satisfy the federal guidelines.

"It doesn't surprise me that there are more cases where people have been interacting more," Adalja said. "Stay-at-home orders are lifting, people are interacting, and the virus didn't go anywhere."

Cases skyrocketed as states began to reopen

In addition to seeing their coronavirus cases rise, states like Arizona, Florida, and Texas have seen increases in their percentage of positive coronavirus tests — a sign that escalating numbers can't be explained by increased testing alone.

Florida's percentage of positive tests jumped from 6% on June 14 to 13% on Thursday. Arizona's percentage of positive tests rose from 16% on June 14 to 23% on Thursday.

"When you see percent positivity rising, that usually means that not every case is being captured by this system," Adalja said.

Florida reported a record number of new coronavirus cases on Friday: nearly 9,000. Though Florida met the White House criteria for reopening when it lifted its stay-at-home order on May 4, the state continued to ease restrictions as cases soared in June.

California and Texas set state records for daily coronavirus cases this week, with California recording more than 7,000 new cases on Tuesday and Texas recording nearly 6,000 new cases on Thursday.

California now has the second-highest tally of coronavirus infections in the country, behind New York: more than 200,000. The state was the first to impose a stay-at-home order (it locked down on March 19), but Gov. Gavin Newsom eased restrictions in May as new daily cases were still rising.

Texas, meanwhile, had one of the shortest lockdowns of any state: Its stay-at-home order lasted less than a month. Cases were still on the rise when the state reopened on May 1.

Texas's weekly hospitalizations rose by 37% this week compared to last.

Texas paused its reopening on Thursday, meaning restaurants and amusement parks won't be able to expand their capacity. The state also reimposed a ban on elective surgeries to free up hospital space. On Friday, Gov. Greg Abbott said bars would close as well.

That was a change from Abbott's prior approach — he told local news station KYTX on June 12 that there was "no real need to ratchet back the opening of businesses."

Indeed, multiple Southern governors told Business Insider last week they weren't considering another round of lockdowns.

"It is exceptionally unlikely that we would choose to close our economy moving forward," Mississippi Gov. Tate Reeves said. "We have to ensure that we protect the lives of Mississippians but also the livelihoods."

Mississippi reported its highest single-day number of coronavirus cases on Thursday: nearly 1,100. The state was among the first to lift its stay-at-home order on April 27, at a time when cases were still rising.

Adalja said another nationwide shutdown probably isn't warranted, nor would it be followed or enforced well — but states with high shares of positive tests should consider more targeted efforts to prevent chains of transmission, like contact tracing.

"We have to do this in a more regionalized manner," he said. "There are going to be new cases. It's just trying to keep them to a level that's manageable."