Emily Feng

A spate of mysterious second-time infections is calling into question the accuracy of COVID-19 diagnostic tools even as China prepares to lift quarantine measures to allow residents to leave the epicenter of its outbreak next month. It's also raising concerns of a possible second wave of cases.

China now makes 200 million face masks a day — more than twenty times the amount it made at the start of February. The leap has been spurred by the outbreak of a new coronavirus. The masks include the lightweight ones that people like to wear in the hope of protection against coronavirus as well as the heavy-duty N95 masks used by health-care workers.

But that's still not nearly enough to meet local demands as well as global orders. So a scramble is now underway in China.

As new cases of coronavirus infection slow in China, the country is gradually getting back to work. Authorities and businesses are taking a range of measures: Local governments are chartering buses for workers. Some companies are buying out entire hotels to house quarantined staff. A temporarily shuttered movie studio is even loaning employees to factories that are short on labor.

Victor Yu is not one of the more than 2,500 people who the Chinese government says were killed by the coronavirus. The 47-year-old resident of Wuhan, epicenter of the outbreak, died Feb. 19 from complications related to renal carcinoma, a common type of kidney cancer. But his family believes that his untimely death is likely related to the coronavirus outbreak.

China has put more than half a billion people under partial or total lockdown in what it is calling an all-out "people's war" against the spread of the new coronavirus. It's equivalent to restricting the movement of the entire population of North America.

More than a month and a half into the outbreak of a new coronavirus in China, the country's economy is still largely in lockdown mode, stalling a global manufacturing powerhouse at the heart of nearly every industrial supply chain. As the crisis continues, businesses big and small are struggling with the disruption the pneumonia-like illness has caused, with effects reaching across the globe.

China's Hubei province expanded its criteria for identifying new coronavirus infections on Thursday, causing a dramatic spike in reported cases at the epicenter of the disease, as Beijing moved to purge provincial party officials amid criticism of their handling of the epidemic.

For the last two weeks, Eden Chen had been glued to her WeChat. A resident of the Chinese coastal city of Wenzhou, Chen and her family had been told to stay indoors, sending only one member out every other day to buy groceries. WeChat, the ubiquitous social media app in China, became an indispensable channel for checking up on relatives, exchanging information about quarantine measures and even getting on a waiting list to order now-scarce face masks.

China says it has launched an investigation into "issues" related to the death on Friday of a doctor whose early efforts to alert his colleagues to the dangers of a new coronavirus were quashed by authorities.

Meanwhile, President Trump spoke with China's leader Xi Jinping to discuss the coronavirus epidemic, which has rapidly gone global since it began in China in December.

Dr. Li Wenliang, an ophthalmologist working in Wuhan, the Chinese city where the epidemic originated, died on Friday local time, weeks after he was hospitalized and treated for a coronavirus infection.

Updated at 8:41 p.m. ET

Millions of people in China have been returning home from the Lunar New Year holiday and heading back to work. The holiday's end date was extended in many cities, from Jan. 31 to Feb. 3, to help slow down the rapidly spreading coronavirus outbreak.

Updated at 8:37 p.m. ET

As the number of coronavirus cases in China jumped dramatically once again on Thursday — to more than 31,000 — other countries where the new strain of viral pneumonia has spread are stepping up efforts to limit the epidemic.

Health authorities in China on Friday reported 31,211 confirmed cases there, with 637 people having died from the virus, officially known as 2019-nCoV, that was first identified in December. Nearly 200 other cases have appeared outside of China and Hong Kong, with one additional death, in the Philippines.

Updated at 7:19 p.m. ET

First came Liu Xiaohong's fever and a constant, throbbing ache. Then six days later, on Jan. 31 and with her fever still raging, Liu desperately rushed by bike to the nearest hospital; taxi services had been suspended days earlier as part of a citywide lockdown.

Doctors did a CT scan of Liu's lungs and concluded that day that she likely had the new coronavirus. Twelve days after falling ill, Liu is now waiting in a makeshift isolation ward for confirmation from a virus screening test so she can finally be admitted to a hospital.

Updated at 7:58 p.m. ET

Hong Kong confirmed its first death from the novel coronavirus on Tuesday as health workers in the territory were on their second day of a walkout aimed at forcing closure of the border with mainland China — the epicenter of the epidemic.

A 39-year-old man who had visited Wuhan, China, where the virus first appeared, died at Hong Kong's Princess Margaret Hospital on Tuesday morning, the hospital confirmed.

Updated at 7:55 p.m. ET

The 24 American students who signed up for Middlebury College's spring language program housed at Beijing's Capital Normal University were expecting tough homework assignments in Mandarin and a chance to explore a new country on weekend trips.

More than a dozen cities in the Chinese province of Hubei are under official lockdown. And some cities and villages are taking it upon themselves to seal off their communities — even if their actions aren't legal.

It's all to prevent the spread of a new strain of coronavirus that has killed over 130 people and sickened more than 5,900 in China.

What do these measures consist of? And do scientists think they will help contain this rapidly spreading virus?

The strictest quarantine is in Wuhan, a city of 11 million that's the epicenter of the outbreak.

Updated at 6:35 p.m. ET

Construction workers in China were scrambling to build a makeshift quarantine and treatment facility on the outskirts of Wuhan, the epicenter of a rapidly spreading new viral pneumonia that has killed 41 people and infected moe than 1,000 others in the country.

Updated at 9:50 p.m. ET

Wuhan's public health authorities say they are in a "state of war" as they quarantine the Chinese city in an attempt to halt the spread of a never-before-seen strain of coronavirus.

"Strictly implement emergency response requirements, enter into a state of war and implement wartime measures to resolutely curb the spread of this epidemic," urged a committee of Wuhan's top officials. "Homes must be segregated, neighbors must be watched."

When Liu, a 31-year-old Chinese insurance firm manager, learned she was pregnant in 2017, she resolved to keep her baby.

She tried to hide the fact that she was unmarried and pregnant from her colleagues at the private insurance firm where she works in Shanghai. She paid her own hospital bills rather than rely on public insurance and risk exposing her secret to the hospital and her employer.

For the last 15 years, Addgene has dedicated itself to accelerating medical research. The nonprofit in Watertown, Mass., does so by sharing research materials globally, like chromosomal DNA, used in the search for breakthrough medical cures.

That could soon change.