States are rolling back lockdowns, but the coronavirus isn’t done with the U.S.

Cases are rising in nearly half the states, according to an Associated Press analysis, a worrying trend that could intensify as people return to work and venture out during the summer.

In Arizona, hospitals have been told to prepare for the worst. Texas has more hospitalized COVID-19 patients than at any time before. And the governor of North Carolina said recent jumps caused him to rethink plans to reopen schools or businesses.

There is no single reason for the surges. In some cases, more testing has revealed more cases. In others, local outbreaks are big enough to push statewide tallies higher. But experts think at least some are due to lifting stay-at-home orders, school and business closures, and other restrictions put in place during the spring to stem the virus’s spread.

The virus is also gradually fanning out.

“It is a disaster that spreads,” said Dr. Jay Butler, who oversees coronavirus response work at the U.S. Centers for Disease Control and Prevention. “It’s not like there’s an entire continental seismic shift and everyone feels the shaking all at once.”

That is also happening globally. Places that suffered early on such as China, Italy and Spain have calmed down but Brazil, India and other countries that were spared initially are seeing large increases. The world is seeing more than 100,000 newly-confirmed cases every day, according to data from Johns Hopkins University,

The virus first landed on the U.S. coasts, carried by international travelers infected abroad. For months, the epicenter was in northeastern states. More recently, the biggest increases have been in the South and the West.