Rates of severe disease may be staying at relatively low levels, but experts agree that there are probably more infections than the current surveillance systems can capture.

“There is more transmission out there than what the surveillance data indicates,” said Janet Hamilton, executive director of the Council of State and Territorial Epidemiologists. “And we should be paying attention to it, because we are starting to see an increase.”

Weekly hospital admissions have nearly doubled over the past month, including a 19% bump in the most recent week, CDC data shows. And a sample of laboratories participating in a federal surveillance program show that test positivity rates have tripled in the past two months.

There are some hopeful signs: Biobot data shows that wastewater levels may be starting to flatten, and relatively low hospitalization rates suggest that there may be a lower risk of severe disease for many.