Chinese authorities Thursday moved to lock down three cities that are home to more than 18 million people in an unprecedented effort to contain a new virus that has sickened hundreds and spread to other parts of the world during the busy Lunar New Year travel period.
"Party committees, governments, and relevant departments at all levels must put people's lives and health first," President Xi Jinping said Monday. "It is necessary to release epidemic information in a timely manner and deepen international cooperation."
China is keen to avoid repeating mistakes with its handling of SARS, another virus, in 2003. For months, even after the illness had spread around the world, China parked patients in hotels and drove them around in ambulances to conceal the true number of cases and avoid the World Health Organization experts.
In the current outbreak, China has been credited with sharing information rapidly, and President Xi has emphasized that as a priority.
On Thursday, police, SWAT teams, and paramilitary troops guarded Wuhan's train station, where metal barriers blocked the entrances at 10 a.m. Only travelers holding tickets for the last trains out were allowed to enter. Normally bustling streets, shopping malls, restaurants, and other public spaces in the city of 11 million people were eerily quiet.
In addition to shutting down the train station, authorities closed the Wuhan airport and halted ferry, subway, and bus service. Police checked all vehicles entering the city but did not close off the roads.
Authorities announced similar measures would take effect Friday in the nearby cities of Huanggang and Ezhou. In Huanggang, theaters, internet cafes, and other entertainment centers were also ordered closed.
Seventeen people have died in the outbreak, all of them in and around Wuhan.
Close to 600 people have been diagnosed with the virus, the vast majority of them in Wuhan, and countries around the world have begun monitoring incoming airline passengers.
The lockdowns are unprecedented in size, embracing more people than the population of New York City, Los Angeles, and Chicago combined.
In the capital, Beijing, authorities canceled "major events" indefinitely, including traditional temple fairs that are a staple of holiday celebrations, in order to "execute epidemic prevention and control."
"To my knowledge, trying to contain a city of 11 million people is new to science," Gauden Galea, the WHO's representative in China, said in an interview. "It has not been tried before as a public health measure. We cannot at this stage say it will or it will not work."
Jonathan Ball, a professor of molecular virology at the University of Nottingham in Britain, said the unprecedented lockdowns appear to be justified scientifically.
"Until there's a better understanding of what the situation is, I think it's not an unreasonable thing to do," he said. "Anything that limits people's travels during an outbreak would obviously work."
But Mr. Ball cautioned that any such quarantine should be strictly time-limited. He added: "You don't want to antagonize communities, so you have to make sure you communicate effectively about why this is being done. Otherwise you will lose the goodwill of the people."
In China, the illnesses from the newly identified coronavirus first appeared last month in Wuhan, an industrial and transportation hub in central China's Hubei province. Other cases have been reported in the United States, Japan, South Korea, and Thailand. Singapore, Vietnam, and Hong Kong reported their first cases Thursday.
Most of the illnesses outside China involve people who were from Wuhan or had recently traveled there.
The sharp rise in illnesses comes as millions of Chinese travel for the Lunar New Year, one of the world's largest annual migrations of people. Chinese are expected to take an estimated 3 billion trips during the 40-day spike in travel.
Analysts predicted cases will continue to multiply, although the jump in numbers is also attributable in part to increased surveillance.
"Even if [cases] are in the thousands, this would not surprise us," Mr. Galea, the WHO's representative said, adding, however, that the number of those infected is not an indicator of the outbreak's severity, so long as the mortality rate remains low.
WHO convened its emergency committee of independent experts on Thursday to consider whether the outbreak should be declared a global health emergency, after the group failed to come to a consensus on Wednesday.
The U.N. health agency defines a global emergency as an "extraordinary event" that constitutes a risk to other countries and requires a coordinated international response.
A declaration of a global emergency typically brings greater money and resources, but may also sow fear and prompt nervous governments to restrict travel and trade to affected countries. The announcement also imposes more disease-reporting requirements on countries.
Declaring an international emergency can also be politically fraught. Countries typically resist the notion that they have a crisis within their borders and may argue strenuously for other control measures.
This story was reported by The Associated Press. AP journalists Shanshan Wang in Shanghai, Maria Cheng in London, and Krista Larson in Dakar contributed to this report.