NEW YORK — The worldwide race to protect people against unwitting coronavirus carriers intensified today, pitting governments against each other as they buy protective gear and prompting new questions about who should wear masks, get temperature checks or even be permitted to go outside.

In the Chinese city of Wuhan, where the pandemic began in December, a green symbol on residents’ smartphones dictates their movements. Green is the “health code” that says a user is symptom-free and it’s required to board a subway, check into a hotel or enter the central city of 11 million. Serious travel restrictions still exist for those who have yellow or red symbols.

In northern Italy, the country with the most virus deaths in the world at over 13,000, guards with thermometer guns decide who can enter supermarkets. In Los Angeles, the mayor has recommended that the city’s 4 million people wear masks.

And a top health official in France’s hard-hit eastern region said American officials swooped in at a Chinese airport to spirit away a planeload of masks that France had ordered.

“On the tarmac, the Americans arrive, take out cash and pay three or four times more for our orders, so we really have to fight,” Jean Rottner, who is both a political leader in the eastern region and an emergency room doctor in Mulhouse, told RTL radio.

A study by researchers in Singapore on Wednesday estimated that around 10% of new infections may be sparked by people who carry the virus but have not yet suffered symptoms.

In response, the U.S. Centers for Disease Control and Prevention changed how it defined the risks of infection, saying essentially that anyone may be a carrier, whether they have symptoms or not. Neither it nor the World Health Organization have changed their guidance against having everyone wearing masks.

More than 95% of people who have died of coronavirus in Europe have been older than 60, WHO said today. Spain, meanwhile, reported a record in virus-related fatalities, with 950 deaths in 24 hours even as its infection rate appeared to ease.

But from New York to Los Angeles, U.S. officials warned that the worst is ahead.

“How does it end? And people want answers,” New York Gov. Andrew Cuomo said. “I want answers. The answer is nobody knows for sure.”

New York state’s coronavirus death toll doubled in 72 hours to more than 1,900. Cuomo has already complained that U.S. states are competing against each other for protective gear and breathing machines, or being outbid by the federal government.

President Donald Trump acknowledged that the federal stockpile is nearly depleted of the personal protective equipment needed by doctors and nurses.

“We’re going to have a couple of weeks, starting pretty much now, but especially a few days from now, that are going to be horrific,” he said.

Los Angeles Mayor Eric Garcetti said even a “tucked-in bandanna” could slow the spread of the virus and remind people to keep their distance from each other.

“I know it will look surreal,” he said, donning a mask. “We’re going to have to get used to seeing each other like this.”

In Japan, where masks are a household stable, the government planned to deliver two gauze masks by mail to each of the country’s 50 million households.

In Greece, authorities placed an entire refugee camp under quarantine today after discovering that a third of the 63 contacts of just one infected woman tested positive — and none had showed symptoms.

The country’s top infectious disease expert, Sotirios Tsiodras, noted that experts disagreed on whether masks helped or worsened the virus spread.

“This is a pandemic of many uncertainties and question marks,” he said.

Altogether, almost 942,000 people around the world have contracted the virus, according to a tally by Johns Hopkins University. More than 47,500 have died from the virus and another 195,000 have recovered.

The real figures are believed to be much higher because of testing shortages, differences in counting the dead and mild cases that have gone unreported.

In Italy, a new study found a hidden toll from coronavirus in the province of Bergamo, more than doubling the official number of 2,060 for the region at the epicenter of Italy’s epidemic with a new estimation of 4,500.