The number of COVID-19 cases across the United States now has surpassed 35 million.
An NBC News tally late Sunday reported that total, along with nearly 616,800 people who have died from the disease in the nation.
Authorities and health experts stress that the vaccines remain effective at preventing serious illness and death.
So-called "breakthrough infections" of people who have been vaccinated represent less than .08 percent of othe 164 million-plus people who have been fully vaccinated in the United States.
The rapid spread of the delta variant is causing a different kind of spike, in vaccinations.
The seven-day moving average for doses administered now stands at more than 650,000.
That number is up 26 percent from three weeks ago, and states with the lowest vaccination rates are seeing the largest improvements.
The Centers for Disease Control says about 50 percent of Americans now are fully vaccinated.