There have been more COVID-19 cases worldwide in the last four weeks than in the first six months of the pandemic, said Dr. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization.

He again urged people, despite promising news on vaccines, to continue using all tools to interrupt chains of transmission and save lives now.

ABC News' Kirit Radia contributed to this report.

Sen. Rick Scott, R-Fl., announced Friday that he has tested positive for COVID-19.

After returning to Florida last week, Scott came into contact with someone who subsequently tested positive. The Republican senator has been quarantining at his home in Naples since then. He took multiple rapid tests earlier this week, all of which were negative, but a PCR (polymerase chain reaction) test he took Tuesday came back positive Friday morning, according to a press release from his office.

"After several negative tests, I learned I was positive this morning," Scott said in a statement Friday. "I am feeling good and experiencing very mild symptoms. I will be working from home in Naples until it is safe for me to return to Washington, D.C."

Scott is the eighth member of Congress to test positive for COVID-19 just this week.

"I want to remind everyone to be careful and do the right things to protect yourselves and others. Wear a mask. Social distance. Quarantine if you come in contact with someone positive like I did," he said. "As we approach Thanksgiving, we know this holiday will be different this year. But, listen to public health officials and follow their guidance. We will beat this together, but we all have to be responsible."

ABC News' Mariam Khan contributed to this report.

A top U.S. Army general who is co-leading the federal government's COVID-19 vaccine initiative said they will start distributing doses throughout the nation 24 hours after the Food and Drug Administration grants emergency use authorization (EUA).

"We have about 40 million doses of vaccine, give or take, exactly when the EUA comes out," Gen. Gustave Perna, chief operations officer for Operation Warp Speed, told ABC News chief anchor George Stephanopoulos in an interview Friday on "Good Morning America."

"We're going to execute fair and equitable distribution based on the population of the jurisdictions -- jurisdictions identified as the 50 states, eight territories and six metropolitan cities," he added, noting that governors will then "make sure the priority for the execution of the vaccine within the state will be implemented."

"We're going to get it down to the states. The states are going to tell us exactly where they want it to be," the general said. "We will ensure that the vaccine gets there in a timely manner. We'll make an initial push -- once EUA is approved -- of everything we have on the shelf, and then every week we're going to maintain a cadence of delivery of vaccine so the states have access and prior planning knowledge to ensure it gets to the right places and the right times."

Perna said the news that Pfizer and partner BioNTech will submit a EUA request to the FDA on Friday for their COVID-19 vaccine candidate is "really remarkable." He expressed "100% confidence" that Operation Warp Speed's distribution plan will be a success -- a process he said began some six months ago.

"We started with the development, manufacturing. We have taken no shortcuts to this end," he said. "It has been a well regulated and accounted for process that we are ensuring occurs the right way."

The general said Operation Warp Speed has also teamed up with companies like Walgreens and CVS.

"I've sat down with their CEOS and their teams -- very elaborate, very comprehensive, operational plans on how they can partner with states to deliver vaccines from inner cities to rural America," he said, "and I'm incredibly confident that they can do that."

When asked whether outgoing President Donald Trump's refusal to cooperate with President-elect Joe Biden and his transition team has hindered vaccine efforts, Perna replied, "Absolutely not."

Pfizer and partner BioNTech announced they will submit a request on Friday to the U.S. Food and Drug Administration for emergency use authorization of their COVID-19 vaccine candidate.

The submission, which is based on a vaccine efficacy rate of 95% demonstrated in the Phase 3 clinical study with no serious safety concerns to date, will potentially enable use of the drug in high-risk populations in the United States by the middle to end of December.

"Our work to deliver a safe and effective vaccine has never been more urgent, as we continue to see an alarming rise in the number of cases of COVID-19 globally," Dr. Albert Bourla, chairman and CEO of Pfizer, said in a statement Friday. "Filing in the U.S. represents a critical milestone in our journey to deliver a COVID-19 vaccine to the world and we now have a more complete picture of both the efficacy and safety profile of our vaccine, giving us confidence in its potential."

The companies have already initiated rolling submissions with several drug regulatory agencies around the world, including in Australia, Canada, Europe, Japan and the United Kingdom, and plan to submit applications to others in the coming days. The companies said they will be ready to distribute the vaccine within hours after authorization.

Based on current projects, the companies said they expect to produce globally up to 50 million doses in 2020 and up to 1.3 billion doses by the end of 2021.

"Filing for Emergency Use Authorization in the U.S. is a critical step in making our vaccine candidate available to the global population as quickly as possible," Dr. Ugur Sahin, CEO and co-founder of BioNTech, said in a statement Friday. "We intend to continue to work with regulatory agencies worldwide to enable the rapid distribution of our vaccine globally. As a company located in Germany in the heart of Europe, our interactions with the European Medicines Agency (EMA) are of particular importance to us and we have continuously provided data to them as part of our rolling review process."

Pfizer said it's completed its submission to the Food and Drug Administration in which the company requests emergency use authorization for its vaccine.

The FDA is expected to start digging into the efficacy and safety data immediately, and it could make a decision as early as mid-December.

ABC News' Sony Salzman contributed to this report.