Research shows that COVID tends to spike twice annually — once in the winter and once in the summer, and, like past years, cases are starting to go up in much of the country now. But exactly how many people currently have COVID is harder to track now because of a number of changes to the country’s public health organizations.

COVID-19 cases are on the rise again across the United States, with the biggest increases in parts of the South, Southeast and West Coast. The U.S. Centers for Disease Control and Prevention (CDC) estimates that 25 states are seeing growth in COVID cases as a summer wave appears to be starting,

The data suggests another summer of illness could be in the offing as people get more out of date with vaccination.