Delta Variant

The CDC sent in a team to investigate a delta variant hotspot in Mesa County, Colo. That didn't stop tens of thousands of people from flocking to the state's largest country music festival.

The CDC just released new estimates showing the highly contagious delta variant now accounts for 51.7% of cases in the U.S. In some parts of the country, the strain is responsible for 80% of cases.

The delta variant is the fast-moving strain of the coronavirus now found in 96 countries. It's expected to be the dominant variant in the U.S. within weeks.

Cases remain low in Spain, Germany and France, but health ministers there say the fast spread of the delta coronavirus strain elsewhere shows a serious threat.

NPR's Leila Fadel talks to Dr. Anthony Fauci about the CDC declaring the Delta variant of COVID-19 a concern, and how vaccines and booster shots fit into the discussion of combating variants.

The variant accounts for more than 6% of all infections in the U.S. and in some Western states is responsible for more than 18% of cases.