School district cancels classes due to staff absences

A pandemic of the novel coronavirus has now killed more than 772,000 people worldwide.

Over 21.7 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 national governments are hiding or downplaying the scope of their outbreaks.

Since the first cases were detected in China in December, the United States has become the worst-affected country, with more than 5.4 million diagnosed cases and at least 170,434 deaths.

Monday's headlines:

Here's how the news developed on Monday. All times Eastern.

7:35 p.m.: NYC gyms not reopening anytime soon, mayor says

Gyms in New York City won't be opening next week, New York City Mayor Bill de Blasio said hours after an announcement that fitness facilities in the state could reopen as early as next Monday.

"There's no higher priority than making sure our schools and child care centers are safe for learning in the fall, and the city's dedicated team of inspectors will continue prioritizing that work," de Blasio said in a statement. "While indoor fitness classes and indoor pools will not be opening at this time, we'll be developing a fair and rigorous inspection system for other gym setups in the coming weeks."

Earlier on Monday, Gov. Andrew Cuomo said that gyms in New York state could reopen at a 33% capacity limit with masks worn at all times as early as Aug. 24. Facilities will also have to undergo inspections to stay open.

6:55 p.m.: Kansas City Chiefs to start season with stadium at 22% capacity

When the Kansas City Chiefs kick off their season next month, the Super Bowl champs could have more than 16,000 fans in attendance.

Team officials announced Monday that the Chiefs' Arrowhead Stadium will have a reduced capacity of about 22% to start the season. The stadium normally can hold over 76,000 people.

Local officials, including the Kansas City mayor, health director and EMS medical director, approved the plan, the team said.

Among the stadium's COVID-19 protocols, masks will be required at all times except when eating or drinking, no bags will be allowed inside, hand sanitization stations have been installed throughout the stadium and high-touch areas will be cleaned before, during and after each game with hospital-grade disinfectants.

The team kicks off its season on Sept. 10 against the Houston Texans.

Over 60 players across the NFL have opted out of the upcoming season due to COVID-19 concerns, including three Chiefs, according to ESPN.

4:25 p.m.: UNC Chapel Hill cancels in-person classes after cases rise

After coronavirus positivity rates rose from 2.8% to 13.6% at the University of North Carolina-Chapel Hill, school officials have decided to move all undergraduate in-person classes to remote learning, they announced Monday.

When students started moving into dorms two weeks ago, officials kept buildings at less than 60% capacity and classrooms at less than 30% capacity, the school said. However, 177 students are now in isolation and another 349 are quarantining, officials said.

The undergraduate shift from in-person to remote will go into effect Wednesday. Classes for the graduate, professional and health affairs schools will continue as they were, officials said.

4 p.m.: US Open's top-seeded female player drops out due to COVID-19

Simona Halep, the top-seeded female tennis player at this year's U.S. Open, has dropped out of the tournament due to COVID-19 concerns.

Halep tweeted Monday, "After weighing up all the factors involved and with the exceptional circumstances in which we are living, I have decided that I will not travel to New York to play the @usopen. I always said I would put my health at the heart of my decision."

Halep, who is currently ranked No. 2 in the world, is the 12th singles player to drop out of this year's grand slam tournament. Most of those 12 players cited COVID-19 as a reason.

Ashleigh Barty, who was ranked No. 1, had also previously dropped out due to COVID-19.

The U.S. Tennis Association released its Health and Safety Plan for the U.S. Open earlier on Monday. Players and members of the highest tiered bubble will be tested twice; after two negative results, they will be tested every four days. Members of the tightest bubble will receive access to the National Tennis Center following the first negative test.

The U.S. Open will begin Aug. 31.

2:10 p.m.: Nearly half of adults risk more severe COVID-19 disease due to underlying medical conditions

Nearly half of U.S. adults -- 45.4% -- have a greater risk of more severe coronavirus disease because they are living with one or more underlying medical conditions, according to a CDC study published in the August edition of the Centers for Disease Control and Prevention (CDC) journal, Emerging Infectious Diseases.

Researchers focused on heart disease, diabetes, lung disease (COPD and asthma), hypertension and cancer because those six conditions were associated with a higher death rate, according to early data from China.

People with one or more of these medical conditions are more likely to experience more serious health problems if infected with COVID-19, according to the study.

The older the person is, the greater the risk is, according to the study.

The study was based on self-reported information from telephone surveys. It does not include information from nursing homes and long-term care facilities so this is likely an underestimate of underlying health conditions.

1:30 p.m.: Virus that causes COVID-19 confirmed in mink in Utah

SARS-CoV-2, the virus that causes COVID-19 in humans, was found among mink at two farms in Utah, according to the United States Department of Agriculture's National Veterinary Services Laboratories.

Some people who had contact with the mink were found to have COVID-19, the USDA said.

The number of infected animals was not released.

"After unusually large numbers of mink died at the farms, the Utah Veterinary Diagnostic Laboratory completed necropsies on several of the affected animals," the department said in a statement Monday. "Samples were forwarded and tested presumptive positive for SARS-CoV-2 at the Washington Animal Disease Diagnostic Laboratory. Both laboratories are members of the National Animal Health Laboratory Network. The presumptive positive samples were then sent to NVSL for confirmatory testing."

These are the first confirmed cases of the virus among mink in the U.S. Mink were previously found to have the virus in the Netherlands, Spain and Denmark, the USDA said.

1:10 p.m.: Canadian Football League cancels season

The Canadian Football League announced Monday that it's canceling the fall season instead of moving ahead with the planned shortened season.

"The league lost its number one source of venue -- fans in the stands -- when the COVID-19 pandemic prevented large gatherings," the league said in a statement. "Unlike US-based leagues that can count on television or streaming to provide the lion's share of their revenue, the CFL depends heavily on its live gate."

"Despite months of discussions, the government ultimately declined the CFL's appeal for financial support," the league said.

"Even with additional support, our owners and community-held teams would have had to endure significant financial losses to play in 2020," Commissioner Randy Ambrosie said in the statement. "This outcome after months of discussions with government officials is disappointing. But we're focused now on the long-term future and we will continue to work with the federal and provincial governments in that context."

12:42 p.m.: Expert stresses importance of universal flu vaccine during pandemic

Emory University's infectious disease expert Dr. Rafi Ahmed said in a video briefing Monday that it's critical that the U.S. not forget about the flu as the pandemic moves forward.

In the last decade, flu infections in the U.S. have ranged from 9 million to 45 million per year and deaths have ranged from 10,000 to 60,000 per year, he said.

The vaccine used for influenza changes annually because every year different strains of the virus emerge, which require the development of new vaccines adapted to fight against them, explained Ahmed. Occasionally a more dangerous strain emerges that can lead to a pandemic, like the swine flu in 2009, he said.

Although the current influenza vaccines are effective, there is still room for improvement, he said.

In particular, Ahmed said "we would like to get away from immunizing people every year" and develop a long-term influenza vaccine that might last "five years, ten years, or maybe even longer."

11:50 a.m.: NY gyms can soon reopen at limited capacity

In New York, gyms can open on Aug. 24 at 33% capacity, Gov. Andrew Cuomo said Monday.

Masks will be mandatory at all times, he said, and health guidelines will be enforced including ventilation requirements.

Localities must inspect the facilities before or within two weeks of reopening, Cuomo said, and localities will also make decisions on indoor fitness classes.

New York, once the U.S. epicenter of the pandemic, now has one of the lowest coronavirus rates in the country, Cuomo said.

Of those tested in New York state on Sunday, .71% tested positive for the coronavirus -- the lowest daily number so far, Cuomo said.

11:10 a.m.: LA launches testing, tracing program at schools

The Los Angeles Unified School District -- the nation's second largest school district -- is launching a coronavirus testing and contact tracing program at schools, said Superintendent Austin Beutner.

The district is reopening with virtual learning starting Tuesday.

Staff, students and their families will get regular testing which will be used "to study the impact and effects of reopening," the district said.

"While this testing and contact tracing effort is unprecedented, it is necessary and appropriate," Beutner said in a statement. "This will provide a public health benefit to the school community, as well as the greater Los Angeles area."

It also benefits students' education "by getting them back to school sooner and safer and keeping them there," he said.

"We hope this effort also will provide learnings which can benefit other school systems," he added.

California has more than 625,000 coronavirus cases, higher than any other state in the U.S.

8:15 a.m.: Bolivia's case count tops 100,000 amid protests

More than 100,000 people in Bolivia have now been diagnosed with COVID-19.

The Bolivian Ministry of Health announced the grim milestone on Sunday night, noting that 60% of the diagnosed cases remain active, including 1,198 new infections. There were also 55 additional coronavirus-related fatalities in the past 24 hours, bringing the death toll to 4,058 nationwide.

The South American nation descended into chaos and civil unrest last month after the government decided to postpone the first round of the presidential election again, due to the coronavirus pandemic. The vote, which was initially supposed to be held in May, will now take place on Oct. 18.

Thousands of people have continued to protest in the streets.

7:23 a.m.: Tulsa sees surge in teachers seeking to file wills

A rising number of teachers in Tulsa, Oklahoma, are seeking to file wills amid the coronavirus pandemic and fears of returning to the classroom, according to a report from local ABC affiliate KTUL.

The Tulsa Classroom Teachers Association told KTUL that the requests from teachers to file wills have increased by 200% since May.

Tulsa Public Schools is set to resume classes virtually on Aug. 31.

Teachers told KTUL they are thankful that the school district is starting with distance learning for the first nine weeks and they hope it will be extended if the city's COVID-19 numbers don't go down. They said they're afraid of bringing the virus home to their families.

6:18 a.m.: Arizona school district cancels classes due to staff absences

A school district in Arizona was forced to cancel Monday classes after more than 100 staff members called out.

The J. O. Combs Unified School District in Arizona's Pinal County was set to resume in-person classes but notified parents in a letter dated Friday that "we have received a high volume of staff absences for Monday citing health and safety concerns."

"Due to these insufficient staffing levels, schools will not be able to re-open on Monday as planned," the school district said. "This means that all classes, including virtual learning, will be canceled. At this time, we do not know the duration of these staff absences, and cannot yet confirm when in-person instruction may resume."

The school district added that they "will continue to monitor the situation and will share an update no later than 5:00 p.m. on Monday."

A spokesperson for the school district told Phoenix ABC affiliate KNXV that at least 109 people, including teachers and office staff, have requested not to work.

Last week, the head of the Arizona Health Services Department and the state's superintendent of public instruction laid out a series of guidelines that public schools were urged to use when deciding whether COVID-19 infection rates are low enough to safely reopen for full in-person learning.

5:37 a.m.: India's coronavirus death toll crosses 50,000

India's health ministry recorded 941 additional coronavirus-related deaths in the past 24 hours, bringing the nationwide death toll to 50,921.

The country of 1.3 billion people has the world's fourth-highest death toll from COVID-19, behind the United States, Brazil and Mexico, according to a real-time tally kept by Johns Hopkins University.

More than 2.6 million people in India have been diagnosed with COVID-19 since the pandemic began -- the third-highest count in the world.

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

4:29 a.m.: Another school closes its doors in Georgia amid rising cases

A third school in Georgia's Cherokee County is shuttering due to a growing cluster of coronavirus cases among its students and staff.

The Cherokee County School District announced Sunday that it was temporarily closing Creekview High School in Canton, Georgia, with the hope of resuming in-person classes there on Aug. 31.

"Over this weekend, the number of positive cases at Creekview High School has increased to a total of 25, with 500 of its 1,800 in-person students now under precautionary quarantine, and additional tests pending that would significantly increase the quarantine total," the Cherokee County School District said in a statement. "We understand these closings create hardships and are disappointing to students who want to learn in-person as well as their families, but these are necessary measures to avoid potential spread within our schools."

The school district has also temporarily closed in-person learning at Woodstock High School and Etowah High School, where reopening is also tentatively scheduled for Aug. 31. Remote learning will be in effect for all students at the three schools in the meantime.

Cherokee County reopened its schools on Aug. 3, welcoming back 30,000 students for in-person learning. Since then, at least 1,876 students and 45 staff members from more than a dozen schools have been placed under mandated two-week quarantines, according to data published on the school district's website.

3:45 a.m.: US reports under 1,000 new deaths for 1st time in 7 days

There were 42,048 new cases of COVID-19 identified in the United States on Sunday, according to a count kept by Johns Hopkins University.

Sunday's case count is well below the record set on July 16, when more than 77,000 new cases were identified in a 24-hour reporting period.

An additional 572 coronavirus-related deaths were also recorded Sunday. It's the first time in seven days that the nation has reported under 1,000 new deaths.

A total of 5,403,361 people in the U.S. have been diagnosed with COVID-19 since the pandemic began, and at least 170,052 of them have died, according to Johns Hopkins. The cases include people from all 50 U.S. states, Washington, D.C. and other U.S. territories as well as repatriated citizens.

By May 20, all U.S. states had begun lifting stay-at-home orders and other restrictions put in place to curb the spread of the novel coronavirus. The day-to-day increase in the country's cases then hovered around 20,000 for a couple of weeks before shooting back up and crossing 70,000 for the first time in mid-July.

An internal memo from the Federal Emergency Management Agency, obtained by ABC News on Sunday night, shows that the nationwide number of new cases over the last week has continued to decrease in week-over-week comparisons, while the number of new deaths has reversed and gone up.

ABC News' Stephanie Ebbs, Alexandra Faul, Josh Hoyos, Aaron Katersky, Josh Margolin, Arielle Mitropoulos, Darren Reynolds and Sony Salzman contributed to this report.