The fast-spreading "Delta" strain recorded the highest infection rates in areas that experienced low vaccination rates.
According to the director of the Centers for Disease Control and Prevention, Rochelle Walinsky, about 93 percent of new infections in recent days have been in counties with vaccination rates below 40 percent.
Preliminary data from recent months indicates that 99.5 percent of deaths due to the Corona virus were from people who had not been vaccinated.
The Centers for Disease Control had previously said that the "delta" mutant has become the dominant strain in the United States, accounting for more than half of all new cases.
The United States is the country most affected by the Corona virus, with more than 43 million infections and more than 622,000 deaths.
