The delta coronavirus variant was classified as a "variant of concern" June 14, and its presence in the U.S. has only grown since.
"The delta variant is currently the greatest threat in the U.S. to our attempt to eliminate COVID-19," Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, said during a June 22 White House news conference.
Here are five facts to know:
1. As of June 22, the delta coronavirus variant accounts for 20 percent of all new COVID-19 cases in the U.S., up 10 percentage points from about two weeks ago.
2. The CDC estimates the delta variant to be about 40 to 60 percent more transmissible than the original strain.
3. Recent projections from the COVID-19 Scenario Modeling Hub predict that the strain could prompt moderate surges in regions with high proportions of unvaccinated people as early as July.
4. Delta already has spread to at least 92 countries, CNBC reported June 22.
5. The effectiveness of the vaccines two weeks after the second dose of Pfizer-BioNTech was 88 percent effective against the delta and 93 percent effective against alpha, Dr. Fauci said.