"Now, many people in Wuhan are saying they wish the lockdown could have been introduced earlier, as this has turned out to be an unprecedentedly serious public health incident since the founding of the People's Republic of China in 1949," Ye said.

Wuhan, which has a population of 14 million, is a key land and water transportation hub in central China. Before the lockdown was imposed, some 5 million people had left the city for Spring Festival, which fell on Jan 25.

The World Health Organization-China Joint Mission's report on coronavirus disease said that due to such population movement, the number of people infected spread quickly throughout the country, with cases particularly concentrated in cities with the highest volume of traffic with Wuhan. Some of these generated limited human-to-human transmission chains at their destinations.

To effectively reduce sources of infection, the central government took the landmark decision to lock down Wuhan.

Faced with the threat from the virus, the country has rolled out arguably the most ambitious and aggressive disease containment effort in history. The WHO-China Joint Mission's report said this bold approach to contain the spread of a new respiratory pathogen has changed the course of a rapidly escalating and deadly epidemic.

Ding Xiangyang, deputy secretary-general of the State Council, China's Cabinet, said during a news conference on Feb 20, "Making the call to put Wuhan under lockdown wasn't an easy decision." Ding is also a member of the work group sent by the central government to guide epidemic control work in Hubei, particularly in Wuhan.

He said that despite misunderstandings and controversies during the initial period of the lockdown, it has proved effective in stamping out the spread of the virus in the epicenter. "This move has protected the rest of China and the world," Ding said.