Sen. Elizabeth Warren is calling on the Centers for Disease Control and Prevention to clarify and revise its estimates for the risk posed to communities of color by Covid-19.

CNBC obtained a copy of a letter the Massachusetts Democrat sent last week to CDC Director Dr. Robert Redfield that says “by failing to adjust COVID-19 mortality rates by age in its public data releases, the CDC may not be providing an accurate assessment of the increased risk of death and serious illness for communities of color relative to white Americans of the same age.”

“In the United States, age, race, and ethnicity are intertwined; people of color are, on average, significantly younger than non-Hispanic white Americans—an interaction the CDC has largely ignored in its communication about COVID-19 mortality rates,” Warren wrote in the letter dated Nov. 10.