The virus that has infected hundreds in China shows signs of being far worse than SARS, the pandemic that killed nearly 800 people 17 years ago, a prominent virologist has warned after travelling to Wuhan, where the new coronavirus first began to spread.

Yi Guan, who played an important role in tracing the development of SARS, spoke hours before authorities prepared to place a second Chinese city on lockdown, as local officials employ increasingly harsh measures in hopes of controlling the spread of the deadly Wuhan virus. Beginning at midnight Thursday, all public transport will halt in Huanggang and checks mandated for every person entering or exiting the city of 7.5 million, situated 70 kilometres east of Wuhan. All theatres, cafes and entertainment venues will be closed as well. Authorities said they would also close rail stations in nearby Ezhou, a city of one million.

“Conservative estimates suggest that the scale of infection may eventually be 10 times higher than SARS,” said Dr. Guan, director of the State Key Laboratory of Emerging Infectious Diseases at the University of Hong Kong, told China’s Caixin media group on Thursday. Dr. Guan spent two days in Wuhan this week.

The World Health Organization said it would deliberate again on Thursday whether it should declare a global emergency around the 2019-nCoV virus, which causes pneumonia-like symptoms and is believed to have originated at a market that sold wild game.

Ivan Hung, chief of the infectious diseases division at the University of Hong Kong, said the ability to rapidly identify the virus in patients should help authorities to counteract its spread. And, he said, “so far the virus is behaving in a less lethal manner than the SARS.”

Dr. Guan, however, left Wuhan convinced that “the epidemic situation was out of control.”

Most viral outbreaks ”are controllable,” he said. He pointed to SARS, H5N1 and swine fever.

“I’ve experienced so much and I’ve never felt scared before,” he said. “But this time I’m scared.”

By Thursday evening, Chinese authorities had identified 633 confirmed cases, 422 suspected cases and 17 deaths in 30 provinces and regions, including Hong Kong and Macau. Further cases have been confirmed in Taiwan, Thailand, South Korea, Japan and the U.S.

The comments from Dr. Guan mark the strongest warning to emerge from a professional who has travelled to Wuhan, a city of 11 million that on Thursday entered a partial lockdown. At 10 a.m., authorities shut down the city’s public transit and barred the boarding of outbound trains and planes.

Local officials described taking “war-time measures,” state media reported. That included the return of China’s familiar heavy-handed control of information: Censors quickly deleted a post from the Wuhan Health Commission admitting to “long queues and a shortage of beds in fever clinics.” The commission has been an important source of local updates. Numerous people in Wuhan took to social media to say they were unable to get medical treatment — or refused diagnostic tests, calling into question the thoroughness of official statistics, even as the scale of the lockdown pointed to significant concern.

But the draconian measures being undertaken may be too late, Dr. Guan said, pointing to the great numbers of people who had already left Wuhan to return to childhood homes across China before the lockdown was imposed.

“When these people returned to their hometowns, they took the virus to all parts of the country,” he said. In Wuhan, doctors told Caixin that the number of people infected could reach as high as 6,000. Using computer modelling, researchers at Imperial College London now estimate as many as 4,000 cases could exist in Wuhan alone.

Given the incubation period of the virus, Dr. Guan estimated that pneumonia-like symptoms may begin to appear more broadly across China beginning Jan. 25. It called into question whether the nation-wide public rush to wear masks — few faces remained uncovered at airports and train stations across the country Thursday — had also come too late.

Other experts disagreed. “We have got the genetic sequence of the novel coronavirus and the ability to perform rapid diagnosis,” said Dr. Hung, at the University of Hong Kong. “During SARS, we were playing catchup and had no knowledge of the SARS coronavirus until very late stage — likely five to six months after the outbreak.”

At the Beijing West Train Station, a porter on Thursday told passersby that bullet trains passing through Wuhan were being disinfected several times a day. Chinese social media called attention to accounts this week from people encountering frontline workers at state-owned firms who had been told not to wear masks, lest it add to the sense of seriousness. By Thursday, those staff were wearing masks.

Foreign experts have said early indications suggest the virus is not as deadly as early coronavirus pandemics, such as SARS and Middle East Respiratory Syndrome (MERS). The Wuhan virus has so far proven deadly only for older people. Among those who have died to date, the youngest is 48 years old.

The major organs of Chinese state media, however, gave little coverage to the spread of the virus, devoting greater attention to smiling pictures of president Xi Jinping issuing greetings for the Lunar New Year.

It stood in stark contrast to the uncertainty and fear that coursed through Wuhan, where people raced to leave the city early Thursday morning, worried that authorities had declared an open-ended moratorium on trips out of the city. The lockdown appears to have also extended to highways in and out of Wuhan, with state media reporting closures.

“The biggest concern to me is how long this sealing-off will last,” said Li Mei, who operates a popular shop selling flat cakes in Wuhan. “We only know it started at 10 a.m. today, and the buses have stopped.”

At the city’s Wanfangtang Drug Store, a shopkeeper who gave her name only as Ms. Liu described six days of working 8 am to midnight, in an attempt to serve a never-ending queue of customers buying masks, alcohol disinfectant and anti-viral medication.

She was so tired, “I almost passed out,” she said. The shop had run out of many products, and “even more people rushed to our store since the lockdown was announced this morning.”

“It’s obvious,” she added, “that people are feeling a greater and greater sense of panic. But it remains under control — at least they are lining up to make purchases.”

Her store, she said, “is probably the busiest place on the street,” as public spaces in Wuhan emptied of people.

“You can barely see anyone wandering outside,” said Duan Jie, a manager at the Wuhan branch of an LED lighting company. Many aspects of life remained normal: “We can still go out to shop, and go to the supermarket to buy fruit and vegetables to prepare for the blackout period,” he said. But he worried about the sufficiency of the city’s food supplies if the lockdown remains in place for long.

Car owners like him have more options, since only public transit has been halted.

Dr. Guan, however, warned that too little was being done in Wuhan, telling Caixin that too few places were being disinfected. Based on what he saw on Tuesday and Wednesday, “local health protection has not been upgraded at all.”

Mr. Duan had nonetheless cancelled plans to drive with his wife and daughter to his hometown for Lunar New Year celebrations, known in China as Spring Festival. They planned to stay home instead.

But he and others barely grumbled.

Spring Festival without extended family might be lonely.

But “I care more about the situation with this disease, and how to make sure my families all safely get through it,” Mr. Duan said.

“Not leaving Wuhan won’t kill you. But the virus could.”

The Globe and Mail, January 22, 2020