More than 3,000 hospitalized patients each week in January had caught Covid sometime during their stay, more than any point of the pandemic, according to U.S. government data analyzed by POLITICO.

The record surge demonstrates the virulence of the Omicron variant and how even hospitals, where infection control is paramount, provided little refuge.

“Any level of hospital transmission is concerning,” said Aaron Milstone, a professor at the Johns Hopkins Bloomberg School of Public Health who focuses on the prevention of hospital-acquired infections. “The data suggests that hospitals should review their practices and make sure they are doing everything they can to protect patients.”