As America hit its highest-ever single-day increase in coronavirus infections yesterday, new cases of COVID-19 are trending up in 26 states. The picture is especially worrying in 11 states where the number of new cases has grown significantly—by an average of more than 200 more new cases per day when compared to two weeks ago—according to a Fortune analysis of New York Times data.

Texas, where Gov. Greg Abbott today announced a “pause” on the state’s reopening because of the surging case numbers, averaged 1,746 new coronavirus cases per day in the week ending June 10; in the seven-day period ending yesterday, June 24, that figure was 4,549. The average number of new cases per day jumped up by 2,527 in Florida; 1,828 in California; and by 1,616 in Arizona over the two-week period.

“The fact that our most populous states are seeing trends going the wrong way is quite disturbing,” says Howard Koh, a professor at the Harvard School of Public Health and a former assistant secretary of the Department of Health and Human Services. Koh links the worsening situation to the fact that many states began reopening their economies before they met the government’s criteria to do so. But he notes that California followed the guidelines closely and is among the states being challenged now.

“We’re still very humbled by this virus, and we’re still very deep into the first wave, five months and counting,” he says.

There are a handful of states that have seen new case numbers trending in the other direction. Michigan, which was averaging 912 new cases per day two weeks ago, saw that figure fall to an average of 288 cases per day over the past seven days. Maryland and Illinois also saw significant drops in the number of new infections.

“It’s distressing to see 50 states going in 50 different directions in terms of trends and strategies,” says Koh. “This is the time to double down on public health and prevention because that’s what works.”