https://www.nytimes.com/interactive/2020/03/22/world/coronavirus-spread.html
How the Virus Got Out
By Jin Wu, Weiyi Cai, Derek Watkins and James GlanzMarch 22, 2020
The most extensive travel restrictions to stop an outbreak in human history haven’t been enough. We analyzed the movements of hundreds of millions of people to show why.
Four cases grew to dozens by the end of December. Doctors knew only that the sick people had viral pneumonia that did not respond to the usual treatments.
The true size of the outbreak was much larger even then — an invisible network of nearly 1,000 cases, or perhaps several times more.
Estimates from Trevor Bedford, University of Washington, and Lauren Gardner, Johns Hopkins University
With each patient infecting two or three others on average, even a perfect response may not have contained the spread.
But Chinese officials did not alert the public to the risks in December. It wasn’t until Dec. 31 that they alerted the World Health Organization and released a statement — and a reassurance.
“The disease is preventable and controllable,” the government said.
The timing of the outbreak could not have been worse. Hundreds of millions of people were about to travel back to their hometowns for the Lunar New Year.
Here’s how people moved around on Jan. 1, according to a Times analysis of data published by Baidu and major telecoms, which tracked the movements of millions of cell phones.

Travel volume on Jan. 1. Minor routes not shown.
At least 175,000 people left Wuhan just on that day, we found.

Travel from Wuhan on Jan. 1
1月1號就有17萬5千人離開武漢
The departures from Wuhan accelerated over the next three weeks. About 7 million people left in January, before travel was restricted.

Travel from Wuhan on Jan. 21
1.1號至21號有700萬人從武漢離開
Thousands of travelers were infected.

Red dots show proportion of infected travelers, based on estimates from Jeffrey Shaman, Columbia University.
By the time Chinese officials acknowledged the risk of human-to-human transmission on Jan. 21, local outbreaks were already seeded in Beijing, Shanghai and other major cities.

Cases as of Jan. 21

Travel on Jan. 21
Two days later, the authorities locked down Wuhan, and many cities followed in the next few weeks. Travel across China nearly stopped.

Cases as of Jan. 21

Travel on Feb. 4
How the Virus Got Out
By Jin Wu, Weiyi Cai, Derek Watkins and James GlanzMarch 22, 2020
The most extensive travel restrictions to stop an outbreak in human history haven’t been enough. We analyzed the movements of hundreds of millions of people to show why.
Four cases grew to dozens by the end of December. Doctors knew only that the sick people had viral pneumonia that did not respond to the usual treatments.
The true size of the outbreak was much larger even then — an invisible network of nearly 1,000 cases, or perhaps several times more.
Estimates from Trevor Bedford, University of Washington, and Lauren Gardner, Johns Hopkins University
With each patient infecting two or three others on average, even a perfect response may not have contained the spread.
But Chinese officials did not alert the public to the risks in December. It wasn’t until Dec. 31 that they alerted the World Health Organization and released a statement — and a reassurance.
“The disease is preventable and controllable,” the government said.
The timing of the outbreak could not have been worse. Hundreds of millions of people were about to travel back to their hometowns for the Lunar New Year.
Here’s how people moved around on Jan. 1, according to a Times analysis of data published by Baidu and major telecoms, which tracked the movements of millions of cell phones.

Travel volume on Jan. 1. Minor routes not shown.
At least 175,000 people left Wuhan just on that day, we found.

Travel from Wuhan on Jan. 1
1月1號就有17萬5千人離開武漢
The departures from Wuhan accelerated over the next three weeks. About 7 million people left in January, before travel was restricted.

Travel from Wuhan on Jan. 21
1.1號至21號有700萬人從武漢離開
Thousands of travelers were infected.

Red dots show proportion of infected travelers, based on estimates from Jeffrey Shaman, Columbia University.
By the time Chinese officials acknowledged the risk of human-to-human transmission on Jan. 21, local outbreaks were already seeded in Beijing, Shanghai and other major cities.

Cases as of Jan. 21

Travel on Jan. 21
Two days later, the authorities locked down Wuhan, and many cities followed in the next few weeks. Travel across China nearly stopped.

Cases as of Jan. 21

Travel on Feb. 4
1 comment
Stone Li
Log in to comment