The Delta variant of COVID-19 is now the dominant strain worldwide and is driving a surge of deaths around the United States, almost entirely among unvaccinated people, U.S. officials said Friday.

Cases of COVID-19 are up 70 percent over the previous week and deaths are up 26 percent, with most of the surge occurring in counties with below average vaccination rates, U.S. Centers for Disease Control and Prevention Director Rochelle Walensky said during a press briefing.

(With input from agencies)