July 20, 2021 — The nation’s top health officials said Tuesday that the Delta variant of the coronavirus is racing through the country and now is responsible for 83% of all U.S. cases.

That’s a massive increase from a week ago, when Delta was seen as responsible for just more than half of new cases, CDC Director Rochelle Walensky, MD, told a Senate committee.

“The best way to prevent the spread of COVID-19 variants is to prevent the spread of disease, and vaccination is the most powerful tool we have,” she said.

Meanwhile, several states in the South are reporting a large increase in COVID-19 cases, particularly in areas with low vaccination rates, according to The Atlanta Journal-Constitution.

Arkansas, Florida, and Missouri are reporting full-fledged outbreaks, and neighboring states such as Alabama, Georgia, Louisiana, Mississippi, Tennessee, and Texas are following behind.

“4^th wave is here,” Thomas Dobbs, MD, the state health officer for Mississippi, wrote on Twitter on Monday.

Dobbs posted a graph of hospitalizations in Mississippi, which showed numbers climbing dramatically in July after hitting a low in May and June.

“Very sad indeed,” he wrote. “Didn’t have to be this way.”

Mississippi reported more than 2,300 new COVID-19 cases over the weekend, which is the state’s largest 3-day increase in cases since February, according to The Associated Press. Mississippi has one of the lowest COVID-19 vaccination rates in the country.

Florida has become one of the country’s biggest COVID-19 hot spots, now accounting for a fifth of new infections in the U.S., according to NBC News.

In Jacksonville, UF Health broke its record for hospitalized COVID-19 patients, jumping from 86 patients on Sunday to 126 on Monday.

“We’re gaining cases at such a rapid rate, we don’t really know where it’s going to stop,” Chad Neilsen, the director of infection prevention at UF Health, told NBC News.

“We aren’t even thinking a couple of months,” he said. “We’re thinking what’s going to immediately happen in the next week.”