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, US officials said Friday.

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

"This is becoming a pandemic of the unvaccinated," she said.