Life is almost back to normal in much of China. Shops, restaurants, bars, and offices are open for business. Manufacturing activity is picking up. Traffic once again jams the highways of major cities. Three-quarters of China's workforce was back on the job as of 24 March, according to one company's estimate. Wuhan, where the COVID-19 pandemic originated, is lagging, as is the rest of Hubei province—but even there, the lockdown is set to lift 8 April.
China has done what few believed was possible: Bring a blazing epidemic of a respiratory virus to a virtual standstill. On 18 March, the country reported zero locally transmitted cases of COVID-19 for the first time. Since then, only six of such infections have been reported, only one of them in Wuhan. Now, the key question is: Can China keep it that way?
Public health officials worldwide are watching closely. "China is addressing an issue every country and location in the world will eventually face: how to normalize and restore societal activities, while at the same time minimizing disease-related dangers from the outbreak," says epidemiologist Keiji Fukuda of the University of Hong Kong (HKU).
New infections now mostly come from outside: More than 500 cases have been confirmed in incoming air passengers since 18 March. At midnight on Friday, China banned virtually all foreigners from entering the country and required all returning Chinese to be quarantined for 2 weeks, whether coming by air or over land. But there is still danger within the country, as well. The smattering of locally transmitted cases shows severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isn't entirely gone. And the very low case numbers may be deceptive. In its tally, China's National Health Commission does not include people who test positive for the virus but have no symptoms, and local authorities are reportedly suppressing information on new infections to meet the target of zero local cases.
Still, "I believe that there are few local cases," says HKU epidemiologist Ben Cowling. But with most of the population still susceptible to infection, fresh outbreaks remain a constant danger. "How to balance getting back to work and a normal state versus maintaining the current status [of few new cases] is certainly critical," says Ding Sheng, director of the Global Health Drug Discovery Institute at Tsinghua University.
Officials are relaxing restrictions very slowly and methodically, Ding says. Many restaurants at first reopened with shortened hours and for a limited number of customers; now, doors are open to all. Primary and secondary schools in several provinces have reopened, but only in communities free of the disease, and schools must check students' temperatures and watch for symptoms. Universities, where students from around the country mix, remain closed, with classes taught online. Events that draw crowds are still banned or discouraged. Live music venues and gyms in many cities remain closed. There are temperature checks at subway entrances and factory gates.
A number of local governments had allowed cinemas to reopen, but last week the national government decided it was too early and closed all theaters for the time being. And habits developed during the epidemic persist. Face masks are ubiquitous. People keep their distance in public and at work. Millions continue to work from home.
To guard against flare-ups, investigators trace and quarantine close contacts of every newly confirmed COVID-19 case, including those who may be asymptomatic, Wu Zunyou, an epidemiologist at the Chinese Center for Disease Control and Prevention (China CDC), told the communist party newspaper China Daily earlier this week. In another precaution, everyone visiting fever clinics in Beijing and other major cities is now tested for the virus. And many provinces check the health status of migrant workers and others crossing their borders. "Any new transmission will be identified quickly and controlled swiftly," Ding says.
Friday's travel ban—which the government implemented even though it strenuously objected when the United States banned visitors from China in January—addresses the other main risk: reintroduction of the virus from the rest of the world. Flights into China have also been severely curtailed. Chinese citizens who arrive undergo strict screening en route and upon arrival and go into quarantine for 2 weeks.
A European academic who returned to China 1 week before the ban took effect described the process to Science. His temperature was taken twice during the flight and he filled out a form detailing his recent whereabouts, the health status of family members and colleagues, and his use of medications. Another temperature check followed at the Beijing airport, after which the scholar—who asked not to be identified—was escorted to his own apartment for a 14-day quarantine. A community official pasted a quarantine notice across the door jamb, which was removed and replaced for grocery deliveries. Authorities ordered him to a "quarantine hotel" 3 days later, after a fellow passenger on the plane turned positive for COVID-19. The academic remains "very understanding," and says he was treated well. (He says he also got a lot of work done on COVID-19–related economic studies.)
"China is addressing an issue every country and location in the world will eventually face: how to normalize and restore societal activities, while at the same time minimizing disease-related dangers from the outbreak."
- Keiji Fukuda, University of Hong Kong
China's strategy "seems to have been effective thus far in preventing a resurgence," says Benjamin Anderson, an epidemiologist at Duke Kunshan University. But with the virus now circulating around the world, "repeated importations to China will inevitably lead to local transmission," Cowling says. "Authorities will need to get on top of the cases very quickly," he says, in a game of whack-a-mole. Remaining pockets of local infection could be a problem as well, says Ira Longini, a disease modeler at the University of Florida. "The models say the disease will come back once the restrictions are lifted. I hope that's not correct, but I can't imagine why it wouldn't be," Longini says.
Much is at stake. Economists predict China's gross domestic product may shrink 10% in the first quarter of this year, the worst contraction since 1976. With Europe and the United States wrestling with their own epidemics, demand for China's manufactured goods has collapsed—aside from masks and medical equipment and supplies. Recurring COVID-19 outbreaks in China would compound the damage.
The Chinese strategy is aimed at buying time until a vaccine or drugs are available, says George Gao, director of the China CDC. A group led by Chen Wei of the Academy of Military Medical Sciences has already started a phase I study of a candidate vaccine, according to China Daily. Trials are expected to last at least through the end of this year. Dozens of other vaccine studies are underway around the world.
Ding, who lived in Beijing through the worst of the crisis, believes China can keep its guard up until these efforts bear fruit. Although minor flare-ups could happen any time, he says, a large-scale reemergence of COVID-19 "is very unlikely given what we have learned."
With reporting by Jon Cohen, Martin Enserink, and Bian Huihui.