Coronavirus: China got it right by locking down Wuhan, German study says

14-Apr-2020 Intellasia | South China Morning Post | 6:02 AM Print This Post

The citywide lockdowns and other extreme measures used by China to contain the coronavirus were effective in curbing the spread of Covid-19 and led to the outbreak peaking in early February, a Germany study says.

According to the research by academics from the Humboldt University of Berlin, the number of confirmed infections grew rapidly in China in the final two weeks of January but then slowed in early February. The city of Wuhan, where the coronavirus was first identified was placed under total lockdown on January 23.

Physicist Dirk Brockmann and doctoral student Benjamin Maier developed a diffusion model to look at the effects of social distancing and other containment measures. Their findings were published last week in the online edition of journal Science.

Brockmann said that when an infectious disease spread unhindered, an “exponential growth in case numbers can generally be expected”.

“For example, one infected person infects three people, these three people in turn infect three people each and after a very short time, there are many people who have become ill,” he said.

But that growth pattern was not seen in China after the lockdowns in Wuhan and other cities across Hubei province, where the peak in infections was reached on February 7, the study said.

“Since the end of January, the number of cases grew steadily slower and then flattened out,” Brockmann said.

Wuhan is home to about 11 million people and remained under lockdown for 11 weeks. During that time, its borders were sealed, all public transport, including air travel, was suspended, roads were closed, public gatherings banned, and the movement of people tightly controlled. For most people excluding those yet to be given a clean bill of health the restrictions were lifted on Wednesday.

According to the researchers, China’s containment strategies succeeded in shielding the vast majority of its population from infection.

Despite being the most populous nation in the world, China has reported just over 82,000 confirmed coronavirus cases. By comparison, the United States, whose population is about a quarter that of China’s, has had more than 520,000.

The German team said the contact tracing and social distancing measures adopted in China led to fewer contacts between infected and non-infected people, which in turn slowed the spread of the disease.

“If a person infects three more people on average, but then only two people each and then only one person each, the outbreak grows more slowly than exponentially. We call this sub-exponential,” Maier said.

Brockmann said a similar slowdown in the number of new infections after shielding non-infected people from carriers of the pathogen had also been seen in other countries, like Italy.

Targeting the susceptible population and inducing behavioural changes had been shown to be effective in containing an epidemic, and especially in situations where it was unknown how long people with no or only mild symptoms remained infective, the study said.

However, that was not yet the case in every country.

“While we are seeing a slight decrease in new infections in Italy and Spain, this behaviour is not yet beginning to show in Germany,” Maier said.

“So we are currently at a critical point: if the number of contacts continues to fall, the outbreak can be contained. But if this does not happen, the total number of cases will continue to rise. A lot now really depends on our own behaviour.


Category: China

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