The highly transmissible Delta variant has become the dominant coronavirus strain circulating in the U.S., according to federal data
The highly transmissible Delta variant has become the dominant strain of the Covid-19 virus circulating in the U.S., according to federal data. It is spreading rapidly as communities loosen pandemic restrictions and officials struggle to reach unvaccinated people.
The Delta variant, also known as B.1.617.2, made up 51.7% of Covid-19 infections in the two weeks ended July 3, according to genetic sequences from positive Covid-19 tests submitted to the U.S. Centers for Disease Control and Prevention., or B.1.1.7, which had been dominant in the U.S. since March and dropped to 28.7% of Covid-19 infections during the same period, according to the CDC data. A third strain, Gamma, or P.1, has been receding rapidly, now making up 8.9% of infections.