Experts say keeping millions in the city of Wuhan does not help curb the corona virus, but may slow the spread.

Wuhan City in Hubei Province, China, where the onset of acute pneumonia caused by a new strain of the corona family (nCoV), was frozen yesterday. 11 million people stopped coming to railway stations and airports. Ferry, subway and bus services also stop. Police check vehicles in and out of the city.

"It was a very drastic decision, but it did not work," said Canadian physician Neil Rau, an expert on infectious diseases. "This measure does not really prevent the viruses that are contagious. In the case of a virus that is not contagious, this measure is too far and causes tremendous inconvenience."

In addition to Wuhan, seven other cities in Hubei Province were also cordoned off, including Huangjiang, Ngac Chau, Xich Bich, Tien Dao, Tiem Giang, Chi Giang and Loi Xuyen. In Beijing, officials canceled a series of major events during the Chinese New Year to "prevent and prevent the epidemic". The Forbidden City is also closed from today to avoid spreading the disease.

Dr Rau thinks these measures are likely to make people think things are worse than they actually are. "Not only Wuhan, it will even cause negative economic consequences for China's tourism industry," he said.

According to a report by the World Health Organization (WHO), the nCoV virus has spread to many countries such as Thailand, Japan, South Korea, the US, Singapore and Vietnam. 25 people died and more than 830 cases were infected. WHO calls it a "state of emergency in China", but has yet to become a global concern.

Dr Isaac Bogoch, a researcher of infectious diseases and global health at the Toronto General Hospital Research Institute, said the blockade in Wuhan, a city of 11 million people in central China, was "not yet." have seen".

"I have never heard of a travel ban imposed on such a large population. I don't think it works, but it can at least slow the spread," Bogoch said.

The expert referred to the SARS (severe acute respiratory syndrome) pandemic in 2002-2003, which began in Hong Kong and spread to 37 countries, also due to a strain of the corona virus. In response to the epidemic, the Canadian government has isolated about 25,000 residents in the expanded Toronto area. However, this effort ultimately wasted budget and manpower because no cases were detected.

Restrictions on movement or blockade have been used for centuries to prevent infectious diseases. During the Ebola outbreak in West Africa in 2014, Sierra Leone imposed a nationwide three-day blockade for medical teams to visit homes seeking cases.

However, this is not always effective. In 2009, when the A / H1N1 flu pandemic appeared, some countries imposed restrictions on flights to and from Mexico. A study two years later indicated that it only helped spread the disease to other countries about three days later.

"These limited measures do not help prevent the disease. Viruses have the ability to spread into a pandemic scale in a short time," the authors of the study wrote.

Previously, a 2006 study on H5N1 avian influenza prevention measures also concluded that "restricting movement after detecting an epidemic is likely to delay the spread of the virus for a short period of time," but does not affect the number of final cases ".

Even so, Jonathan Ball, professor of virology at Nottingham University, UK, still supports the blockade. "Until the situation is clearer, I think blockade is a reasonable way to deal. Any move to limit movement when an epidemic takes place will work," Ball said, but saved. The authorities should set a time limit with a blockade.

Countries with patients infected with Wuhan pneumonia virus as of January 23. Click on the image to see it in full.