The U.S. Centers for Disease Control and Prevention (CDC) identified the more contagious delta variant as the most dominant strain in the United States, comprising the majority of cases in the country for the two weeks ending Saturday, July 3. The prevalence of the delta variant, B.1.617.2, jumped significantly from June to the beginning of July, going from comprising 30.4 percent of the cases in mid-June and jumping to 51.7 percent for the two weeks ending in early July.