By JON HAWORTH, EMILY SHAPIRO and MEREDITH DELISO, ABC News

(NEW YORK) — The novel coronavirus pandemic has now killed more than 621,000 people worldwide.

Over 15.1 million people across the globe 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, many unreported cases and suspicions that some governments are hiding or downplaying the scope of their nations’ outbreaks.

The United States has become the worst-affected country, with more than 3.9 million diagnosed cases and at least 143,147 deaths.

Here is how the news developed Wednesday. All times Eastern:

10:48 p.m.: Southwest, American to require masks for everyone over 2 years old

Southwest Airlines announced it will require all passengers over the age of 2 to wear a face mask on board.

The airline added that there will be no exceptions. Other airlines have allowed those with certain health concerns to not wear a mask.

“If a Customer is unable to wear a face covering or mask for any reason, Southwest regrets that we will be unable to transport the individual,” the company said in a statement. “In those cases, we hope the Customer will allow us to welcome them onboard in the future, if public health guidance, or other safety-related circumstances, regarding face coverings changes.”

The policy will go into effect on July 27.

American Airlines also announced anyone over 2 would need to wear a face mask, and added it will not allow exemptions.

American, which will put its policy in place July 29, added that customers must wear a face covering “from the time they enter their departure airport and not remove it until they exit their arrival airport.”

9:19 p.m.: White House cafeterias shut down due to positive test

White House staff were informed Wednesday night that two of the campus’ cafeterias have been shut down after an individual that works in the facilities tested positive for COVID, sources confirm to ABC News.

The two cafeterias are not within the White House itself, but instead in the Eisenhower Executive Office Building and New Executive Office Building.

“There’s no reason for panic or alarm,” the email, as described to ABC News, reads. It adds that staff in both facilities have been wearing masks and gloves. The email goes on to say that the White House Medical Unit has already performed contact tracing and sees no need for any White House campus staff to self-quarantine.

The White House has already had staffers test positive in the past, including the vice president’s press secretary.

9:03 p.m.: LA County not planning to roll back any more reopenings

Los Angeles Mayor Eric Garcetti announced that at present there are no plans to close any more businesses or shut down activities.

The threat level, he said, remains at orange — the second-highest level — and is not moving to red.

Positivity rate in the county has decreased from 13.6% last week to 10% this week, the first decline in weeks.

But Garcetti also reiterated that it’s too early tell what effect the recent rollbacks have had until next week or so.

“We will always have our finger on the dimmer switch and we are not afraid to use it,” he said.

There were 64 new deaths and 3,266 cases reported in the county on Wednesday.

7:39 p.m.: South sees record COVID-19 deaths

The South had a record number of COVID-19 fatalities for the second day in a row, according to the latest data from The COVID Tracking Project.

There were 725 deaths reported in the region, up from 592 the day before, accounting for 65% of new fatalities in the U.S. The West had 24%, with 264; the Midwest 9% with 104; and the Northeast 2% with 26.

The South accounted for nearly 60% of new cases in the U.S. on Wednesday, with 39,812, according to the project.

4:20 p.m.: Masks required at NFL games

Fans will be required to wear masks at NFL games this season, Brian McCarthy, the NFL’s vice president of communications, tweeted Wednesday.

Capacity at games, or if fans are allowed to attend at all, is left up to each team.

New York’s Giants and Jets said Monday they will play in front of empty stands.

1:25 p.m.: WHO warns vaccines are never ‘100% effective’

“Vaccines are never 100% effective,” World Health Organization (WHO) emergencies chief Dr. Mike Ryan said on Wednesday.

“So the idea that we’re going to have a (COVID-19) vaccine in 2-3 months, and then all of a sudden this virus is going to go away … I would love to be here saying that to you, but that’s just not realistic,” he said.

As of Tuesday, there are 24 vaccine candidates in clinical evaluation, the WHO said.

Ryan said developing a COVID-19 vaccine will take time and that every precaution will be made to ensure that it is safe and effective.

But he warns that it’ll take time to see how effective the vaccine will be, and how long protection will last.

Vaccines generate immunity in “most” people, Ryan said, pointing to the measles vaccine as an example of a “highly effective” vaccine the provides immunity to approximately 95% of people.

“We don’t know where we are with this,” he said of a potential COVID-19 vaccine.

Ryan added, “There is so much we can do now, and it will be so much easier to get rid of this virus using a vaccine if we’ve already suppressed it,” he said, citing wearing masks, washing hands and social distancing.

“It’s easier to beat your opponent, when you have exhausted your opponent,” Ryan said. “Work as hard as we can now, and work as hard as we can on the vaccine, and put the two together.”

12:45 p.m.: Masks now mandatory in DC

Masks are now mandatory in Washington, D.C. as the district sees a rise in cases, Mayor Muriel Bowser said Wednesday.

Bowser said exceptions will include actively eating and drinking, vigorous exercise that respects social distancing, or being alone in an enclosed office. Children under 3 years old are exempt.

Bowser also said that she will extend a state of emergency order in the District that was set to expire by the end of July. 

12:05 p.m.: Miami Beach to issue fines for not wearing a mask

As COVID-19 surges in Florida, those not wearing face coverings in public spots of Miami Beach will be fined $50 beginning on Thursday, officials said.

“We all need to be serious about flattening the curve and putting this deadly virus behind us,” Mayor Dan Gelber said in a statement Wednesday. “Please do your part and wear a mask.”

11:30 a.m.: Florida has 4 counties with no ICU beds

In hard-hit Florida, just 15% of the state’s adult ICU beds were available Wednesday morning, according to the state’s Agency for Healthcare Administration.

Four counties — Monroe, Nassau, Okaloosa and Putnam — had no available ICU beds, the agency said.

These numbers are expected to fluctuate throughout the day as hospitals and medical centers provide updates.

Florida’s positivity rate was 10.55% as of Wednesday morning.

The state now has 379,619 total cases and 5,458 fatalities.

10:35 a.m.: California is now the state with the most coronavirus cases

California has surpassed New York’s number of coronavirus cases, according to Johns Hopkins data.

As of Wednesday morning, California had over 409,000 cases, while New York had over 408,000.

California’s positivity rate and hospitalization rates are trending upward in the two-week average, according to the state.

Meanwhile, New York’s positivity rate was just 1.29% Tuesday, according to Gov. Andrew Cuomo.

Thirty-one states — including California — are on New York’s travel advisory list. Those traveling from the 31 high-case states must quarantine for two weeks when arriving in New York.

9:35 a.m.: Coronavirus cases rising in kids

Coronavirus cases in children is steadily rising and nearing the level of patients 65 or older, according to internal FEMA memos obtained by ABC News. Children ages 12 to 17 appear to become infected at a higher rate than younger kids.

The memos also outlined coronavirus problems that specific states are facing.

In South Carolina, the test-positivity rate is above 15% and rising, the memos said.

Charleston, Horry and Greenville counties reported the highest number of new cases over the last three weeks, representing 38.4% of new cases in the state, the memo said.

Charleston County has the most significant rate increase in the state.

In the Las Vegas, Nevada, area, fatalities are on the rise, particularly among residents older than 65 with underlying health conditions, the memos said.

Out of 38 acute-care hospitals, six reported experiencing critical staffing shortages, while another six hospitals anticipate critical staffing shortages in the next week, the memos said.

Louisiana is experiencing “broad community spread” across the state. East Baton Rouge, Calcasieu and Jefferson parishes had the highest number of new cases over the last three weeks and represent 26.5% of new cases, the memos said.

Lafayette and Lake Charles are reporting a significant lack of testing supplies, the memos said.

8:25 a.m.: Masks could have ‘very significant impact’ on outbreak within months, CDC director says

Dr. Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), called masks the “most powerful tool” against the coronavirus.

“This is the greatest public health crisis that our nation has faced in more than a century,” Redfield told ABC News’ Good Morning America on Wednesday. “If all Americans would embrace that [masks] as part of their personal responsibility to confront this outbreak, we could actually have a very significant impact on the outbreak that we’re seeing across the country in the next four, six, eight, 10, 12 weeks.”

But when it comes to the idea of a national mask mandate, Redfield said, “the issue is how to motivate all Americans to do that.”

“Some governors have done it, obviously with mandates. Other governors have done it through example. I think our key is just to let the American public know how important this is,” he said.

As the new school year nears, Redfield said he would “absolutely” be comfortable with his grandchildren heading back to their classrooms. Redfield added he only may have “some reservation” about his grandson with cystic fibrosis, “depending on how he could be accommodated in the school.”

“I think it’s really important to get our schools open,” he said. “It’s not public health versus opening the schools or the economy — it’s public health versus public health. I think there really are a number of negative public health consequences that have happened to our K-12 [students] by having schools closed.”

“So it’s so important now to work together with school districts to figure out how they can take our guidelines and operationalize them in a practical way and to do it in a way that is safe,” he continued.

5:11 a.m.: France says it has 208 active clusters of COVID-19 across the country

France has 208 currently active coronavirus outbreaks as of Tuesday, according to the General Directorate of Health, which notes that “the circulation of the virus is increasing.”

Since May 9, 547 grouped cases — or clusters — have been detected but 339 have been closed, said the Directorate General of Health.

Currently, 6,482 people are hospitalized for COVID-19 and 455 patients with a severe form of COVID-19 are currently hospitalized in intensive care.

Just four regions in the country — Ile de France, Grand-Est, Hauts-de-France and Guyana — account for 70% of patients being hospitalized in intensive care.

Elsewhere, in overseas territories owned by France, there are a total of 202 hospitalizations, including 34 in intensive care.

Since the start of the pandemic, 106,296 people have been hospitalized in the country and 79,734 people have returned home.

A total of 30,165 people have died so far in France, including 19,649 people in hospitals and 10,516 in nursing and care homes.

4:50 a.m.: Prime minister hopes Russian coronavirus vaccine will be available in fall

The Russian authorities are hoping to receive a reliable domestic coronavirus vaccine in the fall, Russian Prime Minister Mikhail Mishustin said.

“I do hope that we will receive our own Russian reliable vaccine against coronavirus in the fall,” Mishustin said in the State Duma on Wednesday.

Meanwhile, the number of reported new infections in the country remained below 6,000 for the third day in a row.

Russia confirmed 5,862 new coronavirus infections on Wednesday, bringing the country’s official number of cases to 789,190.

Over the past 24 hours 165 people have died, making the total death toll in the country 12,745.

A total of 9,669 people recovered over the last 24 hours, which brought the overall number of recoveries to 572,053.

2:10 a.m.: RNC attendees in Jacksonville to take ‘in-home’ tests before event, no commitment to requiring masks

Almost a month before Republicans are set to gather in Jacksonville, Florida, for President Donald Trump’s second nomination, in a state seeing a record-breaking surge in coronavirus cases, the Republican National Committee outlined in more detail the safety procedures that will be in place for the nominating event in a memo obtained by ABC News.

Convention-goers heading to Jacksonville for the Republicans celebration are expected to take an “in-home COVID-19 test” before the gatherings in either Charlotte or Jacksonville, paid for by the Republican National Committee.

The Jacksonville-based event will be spread across indoor and outdoor venues, the memo says, with planners set to use “Daily’s Place Flex Field, TIAA Bank Field, Daily’s Place Amphitheater, and others” in a multi-block radius of Jacksonville. The party is also preparing for a smaller-scale gathering, with organizers cutting back the number of attendees by limiting the attendance of alternate delegates and guests of delegates in Jacksonville.

On the night of Trump’s anticipated speech, which is slated for Thursday, guests of alternative delegates won’t be permitted inside the convention venue.

Among those who plan to participate in-person for the event, planners indicated that attendees will be tested more than once, writing in the memo “a variety of COVID testing available before and during the convention activities.” Attendees will be asked to provide consent to allow the testing company to share their results with the RNC.

On-site in Jacksonville, various health and safety precautions will be in-place and will “include, but are not limited to, on-site temperature checks, available PPE, and aggressive sanitizing protocols, and available COVID-19 testing,” according to the memo.

But still, Republicans did not commit to requiring masks at the convention and there was no mention of social distancing throughout the nine-page memo.

“We will follow the local and state health guidelines in place at the time of the convention,” the memo reads.

12:26 a.m.: 59 NFL players test positive for COVID-19

The NFL announced on Tuesday that 59 players have so far tested positive for the novel coronavirus.

Meanwhile, the NFL and the NFLPA announced Monday that they had agreed on COVID-19 testing protocols. Players and team personnel will be tested every day for the first two weeks of training camp, then every other day, as long as their team’s positive test rate is and remains under 5%.

New symptom-based testing guidelines from the league were updated on July 17.

If and when NFL training camps open next week, as currently scheduled, teams’ rosters will include a maximum of 80 players, as opposed to the usual 90, in an effort to help enforce social distancing measures in team facilities. This is according to sources who were on an NFLPA players call Tuesday night discussing details of the league’s latest proposal on coronavirus protocols.

Sources also said the NFL and the union officially agreed Tuesday to the league’s plan to drop all preseason games for the 2020 season. The agreement came a day after the league offered to the union to play no preseason games this summer because of the coronavirus pandemic.

Thus, with Tuesday’s developments, the league and the players’ union are inching closer to an agreement on rules that will govern training camp and the season under these difficult circumstances. Weeks of negotiations seem to be coming to a head, as sources who were on the players’ call Tuesday night said there has been agreement on several issues but work remains to be done on others.

A major issue reportedly concerning players right now is the procedure under which they can opt out of the 2020 season if they are in a high-risk category or they’re simply not comfortable playing amid the pandemic.

One source said the league has offered to give stipends — $250,000 for active roster and $100,000 for practice squad — to players who opt out because they’re in high-risk categories but nothing for players who opt out voluntarily.

The source said the league’s proposal would be that players who opt out would have their contracts “toll” — meaning just slide back a year and pick up next year where they are now — but that the teams would in the meantime retain whatever rights they had to release or trade those players under their current contracts.

The players are seeking better protections due to the unprecedented circumstances.

Copyright © 2020, ABC Audio. All rights reserved.