BEIJING, April 9 (Xinhua) -- China has urged intensified detection and prompt response to people infected with the novel coronavirus but showing no symptoms, according to a circular issued by the Joint Prevention and Control Mechanism of the State Council.

Asymptomatic cases refer to people who tested positive for the coronavirus but develop no symptoms such as fever, cough or sore throat, said the circular, noting that they are infectious and pose a risk of spreading to others.

Screening of asymptomatic infections should be stepped up, targeting close contacts of confirmed patients, people involved in cluster outbreaks, those exposed to COVID-19 and travelers from areas with high risks of infections, said the document.

The regulation also required nationwide hospitals and disease control departments to take prompt actions once asymptomatic carriers are detected.

Medical institutions are ordered to report infections to their superior disease control departments within two hours of asymptomatic COVID-19 carriers being found through a direct web-based system.

Meanwhile, an epidemiological survey including a contact investigation should be completed within 24 hours by disease control departments, according to the regulation.

Once verified, asymptomatic carriers will be put under concentrated medical observation for 14 days and can only be released from quarantine upon two consecutive negative nucleic acid test results, with a sampling interval of more than 24 hours, it added.

An additional 14-day medical observation is still necessary for asymptomatic patients who have been discharged from concentrated quarantine, said the document, asking them to undergo follow-up physical examinations in hospitals over the two weeks.

Close contacts of asymptomatic cases should also be put under concentrated medical observation for 14 days.

Since April 1, the National Health Commission has started to incorporate information on asymptomatic cases in its daily report to timely respond to social concerns.

As of Wednesday, a total of 1,104 asymptomatic cases, including 364 imported from abroad, were still under medical observation on the Chinese mainland, the commission said in its daily report.  ■