Coronavirus updates: Florida COVID-19 cases on verge of grim milestone

The global coronavirus pandemic has now killed more than 806,000 people worldwide, nearly a quarter of those in the U.S.

More 23.2 million people worldwide have been diagnosed with COVID-19, the disease caused by the new respiratory virus, according to data compiled by the Center for Systems Science and Engineering at Johns Hopkins University. The actual numbers are believed to be much higher due to testing shortages, unreported cases and suspicions that some national governments are hiding or downplaying the scope of their outbreaks.

The United States is the worst-affected country, with more than 5.6 million diagnosed cases and at least 176,659 deaths.

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Here's how the news is developing today. All times Eastern. Please refresh this page for updates.

6:10 p.m.: Trump urges plasma donation following FDA authorization

The FDA has issued an emergency authorization for convalescent plasma treatment in hospitalized COVID-19 patients, and President Donald Trump is calling on those who have recovered from COVID-19 to donate plasma.

"I once again urge all Americans who have recovered from the virus to go to coronavirus.gov and sign up and donate plasma today, please," Trump said during a press briefing Sunday evening.

Trump called the FDA's announcement to issue an Emergency Use Authorization for the treatment "truly historic."

"It showed tremendous potential," Trump said, noting that a Mayo Clinic study found the blood plasma treatment reduced COVID-19 mortality by 35%.

Antibodies found in convalescent plasma, the yellow liquid separated from the blood of recovered COVID-19 patients, are harvested and deployed to treat the newly sick.

The White House has provided $270 million to the American Red Cross and other blood centers to collect up to 360,000 units of the plasma, Trump said.

2:02 a.m.: Florida coronavirus cases on verge of grim milestone

Florida is approaching a grim milestone, as total confirmed cases of coronavirus are on the verge of surpassing 600,000. The total number of cases currently stands at 597,597.

New daily cases have been over 4,000 since August 19 so there's a chance the state will pass 600,000 when new cases are reported later today.

If so, Florida would be only the second state to do so, behind California.

What to know about coronavirus:

• How it started and how to protect yourself: Coronavirus explained
• What to do if you have symptoms: Coronavirus symptoms
• Tracking the spread in the U.S. and worldwide: Coronavirus map

1:11 a.m.: 17 more students test positive in Georgia Tech Greek house outbreak

Georgia Tech officials said Saturday that 33 more students have tested positive for COVID-19 on campus, including 17 members of the same Greek residence.

Officials with Sigma Phi Epsilon said Saturday night that the outbreak was at their residence.

At least eight other students in Greek housing tested positive at the end of last week but it is unclear if all of those students live at the Sigma Phi Epsilon house.

"In addition to the cluster of Greek housing residents who live in the same Greek residence near campus reported via a campus communication yesterday, 17 more members of the organization tested positive today," officials wrote.

School officials did not identify which Greek organization was affected, but Sigma Phi Epsilon issued a statement confirming it was their house on Saturday night.

“For the past several days, we have dealt with a spike in COVID-19 cases among our members,” the organization wrote on Instagram. “As of three days ago, our house was locked down to non-residents, and we have been working closely with our Alumni and Volunteer Corporation, the Office of Fraternity and Sorority Life and Georgia Tech Administration to test all other members of our chapter and isolate those positive members, in compliance with requests from administration.”

Officials said all residents in the house have been tested and Georgia Tech is turning the residence into an isolation location. Students who have not tested positive will relocate elsewhere to quarantine.

"If you have had recent contact with any residents of Greek housing, please get tested at one of the free Georgia Tech testing sites," officials wrote.

Students returned to class at Georgia Tech on August 17. Students held a die-in on campus that day, protesting the return to in-person instruction.

At least 251 students at Tech have tested positive for the virus.

ABC News' Ahmad Hemingway, Sasha Pezenik and Elizabeth Thomas contributed to this report.