China Launches Survey To Learn More About Asymptomatic Cases, Immunity

Approximately 11,000 people across ten provinces and cities in China, including Wuhan, will be randomly selected to give blood samples and throat swabs so that researchers can learn more about asymptomatic coronavirus cases, as well as immunity in people with coronavirus infections, according to the Hubei Daily.

The epidemiological survey will include 100 neighborhoods in 13 districts, and will include people who were in Wuhan for at least 14 days between January and March.

On Wednesday, China published data revealing that most coronavirus patients remain symptom-free throughout the infection.

Among 6,764 people who tested positive for infection without showing symptoms, only one fifth of them — 1,297 — have so far developed symptoms and been re-classified as confirmed cases, China’s National Health Commission spokesman Mi Feng said at a briefing in Beijing Wednesday. –Bloomberg

If true, approximately 80% who contract the hyper-virulent coronavirus become silent spreaders, while the 20% who draw the short straw experience a spectrum of symptoms which can last for more than a month – ranging from mild (80% of confirmed cases), to moderate, to critical – up to and including death.

Meanwhile, China is likely facing a second wave of coronavirus cases in November according to Caixin, citing one of the country’s highest-profile medical experts.

As we noted on Tuesday, while countries may be able to bring the deadly pandemic under adequate control by autumn, Zhang Wenhong, who heads Shanghai’s Covid-19 clinical expert team and directs the infectious disease department at one of the city’s top hospitals, said during an online livestream broadcast that this coming winter may include a “second wave” of infections in China and elsewhere.

Zhang’s comments come as Chinese officials gradually ease quarantine restrictions as part of efforts to revive the country’s economy. The East Asian nation, where the previously unknown virus was first detected last year, has seen numbers of daily new cases fall in recent weeks after recording thousands of Covid-19-related deaths and rolling out unprecedented lockdowns.