In early April 2020, China reported thousands of new asymptomatic COVID-19 cases, prompting a comprehensive national study to assess infection rates across the population.
According to a April 16, 2020, article in the respected Chinese outlet Caixin Wang, China identified 6,764 new asymptomatic COVID-19 cases between April 1 and 14. Of these, 588 involved individuals returning from abroad. This underscores the need for enhanced detection, reporting, and management of asymptomatic carriers, who test positive for the virus but show no symptoms like fever or cough—yet remain contagious.
To address this, Chinese authorities launched a rigorous study across nine provinces, including Hubei—home to Wuhan, the epidemic's epicenter. In Wuhan alone, researchers plan to conduct 11,000 serological tests and collect other samples from participants across the city's 13 districts.
Ding Gangqiang, head of the National Epidemic Prevention Center, emphasized that families will form the core sampling units to ensure population representativeness, result accuracy, and reliability. Entire households will participate, provided they resided in the selected districts from January 1 to March 30, 2020. The study also includes outsiders like volunteers, security personnel, and taxi drivers who worked in these areas.
With over 84,000 confirmed cases and more than 4,600 deaths, China faced renewed concerns of a second wave in April 2020. On April 13 alone, 108 new cases were reported—the highest daily tally since March 5—despite the country declaring victory over the initial outbreak in mid-March. Recent scrutiny has also focused on Wuhan's P4 virology lab, developed through a France-China partnership following the 2003 SARS outbreak.
