BEIJING — Major Chinese cities, including Beijing and quarantine-blocked Wuhan, banned all large gatherings over the coming Lunar New Year festival, the most important holiday on the Chinese calendar, in an expanding effort to contain a rapidly spreading coronavirus outbreak.

The announcement Thursday came as authorities expanded travel restrictions imposed on Wuhan to surrounding municipalities, shutting down travel networks and attempting to quarantine about 25 million people — more than the population of Florida. Here is what we know:

●Cases of the virus have been detected around China, including Hong Kong and Macao, and other countries, including Japan, South Korea, Taiwan, the United States and Thailand. Singapore and Vietnam are the latest to join the list.

●At least 26 deaths have been confirmed in China, two of them outside of Hubei province. At least 835 people have been infected.

●U.S.-bound travelers from Wuhan will be routed to five airports for screening: Chicago’s O’Hare, New York’s John F. Kennedy, Atlanta’s Hartsfield-Jackson, and Los Angeles’s and San Francisco’s international airports.

●Residents of Wuhan report empty shelves in stores and express frustration that the government isn’t telling them the full story.

●The World Health Organization declined to declare a global health emergency Thursday, saying it’s too early.


The extreme measures were accompanied by other indications that Communist Party authorities were struggling to control the outbreak, notably the aggressive censorship of any criticism or skepticism on social media.

But some outspoken doctors warned that the controls would not be enough to stop the spread of the pneumonia-like virus, which has killed 26 people, according to China’s National Health Commission. At least 835 people have been infected.

The people who died were between ages 48 and 89, but the vast majority were at the top of that range and almost all of them had existing health conditions. Only two of the deaths occurred outside of the epicenter of Hubei province, of which Wuhan is the capital.

“A bigger outbreak is certain,” said Guan Yi, a virologist who helped identify severe acute respiratory syndrome (SARS) in 2003. He estimated — “conservatively,” he said — that this outbreak could be 10 times bigger than the SARS epidemic because that virus was transmitted by only a few “super spreaders” in a more defined part of the country.

“We have passed through the ‘golden period’ for prevention and control,” he told Caixin magazine from self-imposed quarantine after visiting Wuhan. “What’s more, we’ve got the holiday traffic rush and a dereliction of duty from certain officials.”

The Centers for Disease Control and Prevention announced Thursday that health officials in Texas notified it about a potential case of coronavirus. The CDC said in a statement that it is in communication with state health officials and will share more information as it becomes available.

Health officials in Brazos County, Tex. — which is where Texas A&M University is located, about 100 miles northwest of Houston — said they are investigating a patient who meets the definition of a potential case of the new virus. The patient contracted a respiratory illness within two weeks of traveling in Wuhan and is being isolated at home in accordance with recommendations from the CDC.

In Geneva, the World Health Organization cited Chinese efforts to prevent transmission and the limited number of cases recorded abroad as its reasons for not declaring Thursday that the outbreak was a public health emergency of international concern.

But WHO Director General Tedros Adhanom Ghebreyesus said at a news conference that the decision “should not be taken as a sign that WHO does not think the outbreak is serious or that we’re not taking it seriously. Nothing could be further from the truth.”

He said the emergency committee was divided on whether the outbreak deserved the special designation, but said regardless, the outbreak amounts to “an emergency in China.”

“It has not yet become a global health emergency, but it may become one,” he said.

In general, declaring an international public health emergency gives the WHO director general powers to issue recommendations to other countries, such as urging them not to close borders or restrict trade with a country in the middle of an outbreak. Public health officials say such measures are considered unlikely to stop disease spread and very likely to discourage countries from being forthright about outbreaks.

WHO officials gave the most detailed information so far about the severity of the illness associated with the new coronavirus. Much about how it works is still unknown, Tedros said, including its source, how easily it spreads and its full clinical features. These are all critical factors, experts have said, for declaring a global health emergency.

The most likely source is an animal, WHO said. But officials don’t know which one. And they don’t know the extent of human-to-human spread.

Still, WHO officials said that despite some gaps in knowledge, they have several advantages confronting this outbreak compared with the 2003 SARS outbreak that also originated in China and sickened thousands of people worldwide.

Michael Ryan, executive director of WHO’s Health Emergencies Program, said it was too early to estimate just how severe this virus is and what proportion of people it kills, often referred to as the case fatality rate.

A vaccine is under development for the virus, but that process is not quick, and there are no specific therapies or treatment. Some of the patients who died in China have required extensive ventilator assistance to help them breathe.

As with other epidemics, countries with weaker health systems may come under pressure from the “worried well” who may overwhelm hospitals and clinics. Health officials need to “manage the pressures on the health systems,” Ryan said.

It has not peaked, he added. WHO officials are “grateful” for the partnership with China. In many similar situations, “other countries have not been willing to share at that level,” he said.

The data released by WHO drew criticism from some experts because so much remains unknown. WHO officials said that about 25 percent of cases were severe infections. China has reported the number of sick patients, but has not provided — and may not know — the total number of people infected.

If the total number of infected people is five or 10 times larger than those who have fallen ill and been diagnosed, “we can’t say 25 percent for severe infections without knowing the denominator, the number of people infected,” said Tom Frieden, former director of the Centers for Disease Control and Prevention.

The Lunar New Year holiday, a week-long period when millions of Chinese travel to their hometowns — the biggest human migration on the planet — officially begins Friday.

Ahead of the holiday, authorities initially said that the virus, which began in a Wuhan food market selling exotic animals for consumption, was mild and could not be transmitted among humans. But that changed this week when the number of people infected by the virus, which has an incubation period as long as 14 days, began to rise rapidly.

Even one of the government’s top experts, who had played down the prospects for widespread infection, contracted the virus.

Vietnam and Singapore joined the list of other countries that have detected the virus, with both confirming two cases had been found and were being treated.

Airports around the world, from London to Dubai to Atlanta, have put special screening measures in place to detect passengers arriving from China with fevers.

Authorities in Beijing and the southern city of Guangzhou said they were restricting public gatherings over the Lunar New Year holiday, which officially begins Friday and is often celebrated with large fireworks displays and popular fairs at temples.

The Forbidden City, the old imperial palace in the heart of Beijing and one of China’s top tourist attractions, said it was closing its doors until further notice “to avoid cross-infection caused by the gathering of people.”

Authorities in Wuhan announced even more stringent measures. In addition to banning public gatherings, local officials, wearing masks, announced that the start of the spring semester at all Hubei province schools will be delayed because of the outbreak.

The ruling Communist Party, which initially tried to show transparency after being criticized for covering up the SARS virus outbreak 17 years ago, has now shown signs of reverting to its default position of censoring bad news.

In a post that was online for less than an hour, the Wuhan Health Commission admitted Thursday that it was struggling to respond to the outbreak.

A post from Wuhan Railway saying that 300,000 people traveled by train out of Wuhan on Wednesday, headed to every corner of the country, was also quickly deleted.

Analysts said the heavy-handed reaction underscored the political risks for Chinese leader Xi Jinping and the ruling Communist Party, already under pressure amid an economic slowdown and accused of mishandling an outbreak of swine fever last year, which led to a sharp spike in prices for China’s beloved pork.

“This outbreak may be the biggest threat to Xi and the Party in years, which is why they will stop at nothing to try to control and then eradicate it,” said Bill Bishop, publisher of the influential Sinocism newsletter.

The city of Wuhan pulsated with fear and anger Thursday, as 11 million people absorbed the news that they were being confined to a metropolis-size quarantine zone designed to contain a widening coronavirus outbreak.

The three main railway stations, 13 bus stations, the entire subway network and almost all city bus lines were shut down at 10 a.m. Thursday. Half of the 566 flights scheduled at Wuhan’s international airport for Thursday were canceled, as were 251 ferry sailings on the Yangtze River, according to the Wuhan Transportation Bureau.

Many people flocked to the roads to try to avoid getting caught in the quarantine. Television footage showed health workers in hazmat suits taking motorists’ temperatures as they waited at toll booths.

Others did not make it out. Hubei’s highway management authority closed multiple expressways in and around Wuhan, and Wuhan traffic police confirmed that although vehicles were allowed to come into the city, they were prohibited from going out, except in special cases.

At least four other neighboring districts said they will adopt similar travel restrictions, effectively doubling the number of people in quarantine to 25 million.

In Macao, where one case has been found, the government said it might shut down the territory’s casinos if the epidemic worsens. Macao’s gambling sector is seven times the size of Las Vegas’s. The authorities have called off a public festival to ring in the new year.

Many people in Wuhan were incensed at the sudden announcement of the travel restrictions Thursday.

“I didn’t even receive a notice,” said one woman who found herself stranded at Hankou Railway Station. She had been on her way from Henan province southwest to Sichuan and was changing trains in Wuhan when she got caught up in the suspension.

Some people resorted to extreme measures to escape the travel ban. One man who could not get a taxi to the station to catch an earlier train persuaded a food delivery driver to give him a lift on his scooter. The desperate traveler paid $72 to have the man, who would usually make less than half that in a day, drop him at the station. “We were flying,” he said.

Others thought the ban was warranted.

“I think we can fully understand why they made the decision; they have no alternative,” said Zhu, a 56-year-old university professor in Wuhan who declined to give a full name. “But it’s difficult to tell how effective it will be.”

Still, distrust of authorities is mounting.

Although local authorities said they had enough food for residents and medical supplies to treat patients, Wuhan residents posted photos on social media showing empty shelves in grocery stores. Prices of fresh fruit and vegetables have spiked, with cabbages selling for double the usual amount.

Wuhan authorities have ordered residents to wear masks in public places, but the People’s Daily, the mouthpiece of the Communist Party, posted on social media that the province was short of masks and protective clothing. The post, which was widely shared, was soon deleted.

Speculation swirled that the government had silenced Zhong Nanshan, the renowned respiratory expert who helped discover SARS in 2003 and is known for his bluntness.

Zhong, a member of the National Health Commission’s group of experts investigating the outbreak, had been on Chinese television constantly this week and announced the finding that the coronavirus could pass from human to human. But he has disappeared from screens in recent days and did not answer phone calls from The Washington Post.

As the uncertainty continued, Guan, the virologist who identified SARS, offered a chilling perspective on the outbreak.

“I’ve seen it all: bird flu, SARS, influenza A, swine fever and the rest. But the Wuhan pneumonia makes me feel extremely powerless,” he told Caixin. “Most of the past epidemics were controllable, but this time, I’m petrified.”

Sun reported from Washington. Wang Yuan, Liu Yang and Lyric Li in Beijing and Yasmeen Abutaleb, Siobhán O’Grady and Marisa Iati in Washington contributed to this report.