“Infections may be increasing modestly, but severe disease is very low,” said Elizabeth Carlton, an associate professor for the school at the CU Anschutz Medical Campus and member of the Colorado COVID-19 Modeling Team that provides epidemiological modeling for the state. “My guesses as to what is driving this: immunity to severe disease due to vaccination and the sheer number of infections we had in Colorado” from December through February because of the omicron wave.