**This post just shows part of the news**
The team began in Beijing and then split into two groups that, all told, traveled to Shenzhen, Guangzhou, Chengdu, and the hardest hit city, Wuhan. They visited hospitals, laboratories, companies, wet markets selling live animals, train stations, and local government offices. “Everywhere you went, anyone you spoke to, there was a sense of responsibility and collective action, and there’s war footing to get things done,” Aylward says.
The group also reviewed the massive data set that Chinese scientists have compiled. (The country still accounts for more than 90% of the global total of the 90,000 confirmed cases.) They learned that about 80% of infected people had mild to moderate disease, 13.8% had severe symptoms, and 6.1% had life-threatening episodes of respiratory failure, septic shock, or organ failure. The case fatality rate was highest for people over age 80 (21.9%), and people who had heart disease, diabetes, or hypertension. Fever and dry cough were the most common symptoms. Surprisingly, only 4.8% of infected people had runny noses. Children made up a mere 2.4% of the cases, and almost none was severely ill. For the mild and moderate cases, it took 2 weeks on average to recover.
A critical unknown is how many mild or asymptomatic cases occur. If large numbers of infections are below the radar, that complicates attempts to isolate infectious people and slow spread of the virus. But on the positive side, if the virus causes few, if any, symptoms in many infected people, the current estimated case fatality rate is too high. (The report says that rate varies greatly, from 5.8% in Wuhan, whose health system was overwhelmed, to 0.7% in other regions.)
To get at this question, the report notes that so-called fever clinics in Guangdong province screened approximately 320,000 people for COVID-19 and only found 0.14% of them to be positive. “That was really interesting, because we were hoping and maybe expecting to see a large burden of mild and asymptomatic cases,” says Caitlin Rivers, an epidemiologist at the Johns Hopkins Center for Health Security. “That piece of data suggests that’s not happening, which would imply that the case fatality risk might be more or less as we currently have.” But Guangdong province was not a heavily affected area, so it is not clear whether the same holds in Hubei province, which was the hardest hit, Rivers cautions.
Much of the report focuses on understanding how China achieved what many public health experts thought was impossible: containing the spread of a widely circulating respiratory virus. “China has rolled out perhaps the most ambitious, agile, and aggressive disease containment effort in history,” the report notes.
The most dramatic—and controversial—measure was the lockdown of Wuhan and nearby cities in Hubei province, which has put at least 50 million people under a mandatory quarantine since 23 January. That has “effectively prevented further exportation of infected individuals to the rest of the country,” the report concludes. In other regions of mainland China, people voluntarily quarantined and were monitored by appointed leaders in neighborhoods.
Chinese authorities also built two dedicated hospitals in Wuhan in just over 1 week. Health care workers from all over China were sent to the outbreak’s center. The government launched an unprecedented effort to trace contacts of confirmed cases. In Wuhan alone, more than 1800 teams of five or more people traced tens of thousands of contacts.
Aggressive “social distancing” measures implemented in the entire country included canceling sporting events and shuttering theaters. Schools extended breaks that began in mid-January for the Lunar New Year. Many businesses closed shop. Anyone who went outdoors had to wear a mask.
Two widely used mobile phone apps, AliPay and WeChat—which in recent years have replaced cash in China—helped enforce the restrictions, because they allow the government to keep track of people’s movements and even stop people with confirmed infections from traveling. “Every person has sort of a traffic light system,” says mission member Gabriel Leung, dean of the Li Ka Shing Faculty of Medicine at the University of Hong Kong. Color codes on mobile phones—in which green, yellow, or red designate a person’s health status—let guards at train stations and other checkpoints know who to let through.
“As a consequence of all of these measures, public life is very reduced,” the report notes. But the measures worked. In the end, infected people rarely spread the virus to anyone but members of their own household, Leung says. Once all the people in an apartment or home were exposed, the virus had nowhere else to go and chains of transmission ended. “That’s how the epidemic truly came under control,” Leung says. In sum, he says, there was a combination of “good old social distancing and quarantining very effectively done because of that on-the-ground machinery at the neighborhood level, facilitated by AI [artificial intelligence] big data.”
**For the whole news go to: https://www.sciencemag.org/news/2020/03/china-s-aggressive-measures-have-slowed-coronavirus-they-may-not-work-other-countries **