The number of new daily coronavirus infections in the U.S. continued to rise this past week, driven by upward trends in nearly half the states that have pushed total cases in the country past 7 million. At the same time, a recent study suggests the vast majority of Americans haven’t been exposed, far below what’s required to quell the virus’s spread through “herd immunity.”

Daily cases were largely on a downward trend through August and early September from highs in July, but are now going up again.

According to the Johns Hopkins University Coronavirus Tracker, the U.S. reported more than 55,000 new cases on Friday. In total, the U.S. has more than 7,074,000 infections with 204,000 dead as a result of COVID-19.

Overall, about two-dozen states and territories reported an upward trend in new infections, with some states setting and breaking records in days.

In Wisconsin, the state’s Department of Health said it had identified 2,817 new infections on Saturday — its highest daily total since the pandemic began. It broke the record of 2,533 new infections from Sept. 18.

Earlier in the week, Wisconsin Gov. Tony Evers declared a new public health emergency. In issuing his executive order Tuesday, Evers noted that an increase in infections among young people, particularly on campuses, was helping to drive the surge.

Later in the week, Evers announced he was allocating $8.3 million for testing at colleges and universities.

“Wisconsin is now experiencing unprecedented, near-exponential growth of the number of COVID-19 cases in our state,” Evers said in a video posted to social media this week.

Elsewhere in the Midwest, South Dakota continued to see a surge in cases. The state’s department of health reported 579 new cases on its website Saturday — it’s highest daily total since the pandemic began, according to data from Johns Hopkins.

Other states reporting record surges this week include Utah, which reported 1,411 new cases Friday. Montana also broke its daily record on Saturday with 346 new cases.