Global COVID-19 cases top 16 million, was 15 million only 4 days ago

The novel coronavirus pandemic has now killed more than 646,000 people worldwide.

Over 16 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 4.2 million diagnosed cases and at least 146,788 deaths.

Sunday's headlines:

Here is how the news developed on Sunday. All times Eastern.

5:42 p.m.: Duke will only allow freshmen, sophomores in campus housing

To reduce its residential population, Duke University will only allow freshmen and sophomores to live in on-campus housing this fall.

In a message sent to faculty, staff and students on Sunday, Duke President Vincent E. Price said the decision was based on the spread of COVID-19 both in North Carolina and nationally.

"It is sadly clear that the persistence and spread of COVID-19 are trending in the wrong direction nationally, in North Carolina, and in Durham; and based on the latest guidance from Duke medical experts and public officials, we anticipate that matters may worsen in the weeks ahead," Price said. "In light of these worrisome conditions and to address the increased prevalence of the coronavirus, we must further reduce the density of our campus residential population."

The move will decrease Duke's residential population by about 30%, Price said. In addition to freshmen and sophomores, students who have specific needs for campus housing due to personal or academic reasons may also be eligible for on-campus housing.

Juniors and seniors will have first priority for campus housing in the spring, Price said. In the meantime, they can live in the Durham area or do remote learning. All students, regardless of where they will live, will do most of their course work remotely, Price said.

North Carolina has 112,713 confirmed cases of COVID-19, according to state data. As of Saturday, the testing positivity rate was 9%.

1:15 p.m.: Mexican state health secretary has died after contracting virus

The health secretary of a Mexican border state who tested positive for COVID-19 has died, the governor of Chihuahua confirmed in a statement.

Dr. Jesús Enrique Grajeda Herrera died Sunday morning at a Mexican hospital after suffering cardiac failure, Gov. Javier Corral said in a Facebook post. Corral did not definitively say Grajeda Herrera died of COVID-19.

The health secretary contracted the virus on July 2 after traveling to the state of Tamaulipas to meet with officials there, including Gov. Javier Garcia Cabeza de Vaca, who hours later tested positive for the coronavirus.

Grajeda Herrera was admitted to a Chihuahua hospital on July 5 and had been showing signs of improvement.

10:55 a.m.: Florida sees another 9,000-plus cases in last 24 hours

The state of Florida has seen an increase of 9,344 cases and 78 new deaths in the last 24 hours, according to the Florida Department of Health.

Florida now has 423,855 total cases and 5,972 deaths since the coronavirus pandemic began.

The state currently has an overall positivity rate of 11.06%, officials said.

An additional 334 people were hospitalized on Saturday for COVID-19, bringing the statewide total of active hospitalizations to 8,925. In total, 24,064 people have been hospitalized in the state because of the coronavirus.

3:58 a.m.: Teen girl is El Paso’s youngest virus victim, among 3 new deaths to close out deadliest recorded week

A teenage girl, El Paso's youngest victim of the coronavirus, was among three new deaths reported Saturday morning by health officials to close out the deadliest recorded week of the entire pandemic for the region.

The number of fatalities for the week reached 42, which not only set a record for El Paso but also surpassed the weekly death in neighboring Ciudad Juarez for the first time since the outbreak began.

El Paso's Mexican sister city tallied just over half of the Sun City's weekly death toll at 26, which was its lowest count in months.

It was not immediately known if the teenage victim noted in Saturday's health department death report was 19-year-old Dariana Rubio, who died earlier this week from what her family believed was the virus.

The other two latest deaths were a man in his 60s and a woman in her 70s, both with underlying health conditions.

The health department also reported 221 newly confirmed virus cases on Saturday, bringing the total number of infections to 12,971.

Of those, officials indicated 3,402 were active cases -- while 9,348 El Pasoans were listed as having recovered. Research shows some recovered persons can still have long-term health issues stemming from the virus.

For the week, there were 1,839 new virus cases recorded, which was down from the 2,033 infections occurring last week.

On Saturday morning, 310 people were hospitalized, which was a drop by seven patients from Friday. Of those in the hospital, 97 were listed in intensive care Saturday, marking the first time in ten days that the ICU count dropped below 100. Ventilators are currently required by 49 of the hospitalized patients.

3:35 a.m.: Total number of COVID-19 cases worldwide now more than 16 million

The number of confirmed COVID-19 cases worldwide has now passed 16 million, according to Johns Hopkins University.

The total number of global confirmed cases now stands at 16,048,100 while the total number of deaths globally stands at 644,556.

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 number of confirmed COVID-19 cases around the world topped the benchmark of 15 million only four days ago on July 22.

Editor’s Picks

'COVID parties' sound alarming, but are they really happening?

COVID-19 rashes: How your skin can be a sign of the virus

Trump cancels Florida portion of GOP convention as coronavirus cases surge: 'Not the right time'

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

1:34 a.m.: Spain removed from UK's travel corridors exemption list, travelers now required to self-isolate

Spain is no longer on the U.K.'s travel corridor list and people arriving into England, Wales, Scotland and Northern Ireland from Spain will be required to self-isolate.

The British government has said that those already in Spain can stay for the remainder of their vacation and will have to self-isolate upon return.

The Foreign Commonwealth Office (FCO) is now advising against all but essential travel to mainland Spain which does not cover the Canary Islands or the Balearic Islands because travel advice is based on the risk to the individual traveler and COVID-19 infection rates are lower there than mainland Spain.

"Protecting public health is our absolute priority and we have taken this decision to limit any potential spread to the U.K.," a government spokesperson said in a statement released to the media. "We’ve always been clear that we would act immediately to remove a country where necessary. Both our list of quarantine exemptions and the FCO travel advice are being updated to reflect these latest risk assessments."

ABC News' Jim Parker, Scott Withers, Joshua Hoyos and Alexandra Faul contributed to this report.