BEIJING: China on Thursday unveiled a new trial protocol warranting re-testing of the recovered coronavirus patients besides intensifying the screening of asymptomatic cases as concerns grew over the second wave of virus infections in the country.The move comes a day after China lifted the 76-day lockdown in Wuhan, where the pandemic originated.China's National Health Commission (NHC) on Thursday reported 63 new confirmed cases of the coronavirus, including 61 imported ones taking the total to 1,104 cases.Two more persons were killed due to the disease, taking the death toll in the country to 3,335. The overall coronavirus cases have reached 81,865 in the country.After nearly three months of grim battle against the coronavirus, China is fast returning to normalcy with factories and business humming back to activity amid concerns over coronavirus rebound due to a steady rise of new infections, especially coming from thousands of Chinese returning from abroad.As the 76-day lockdown of Wuhan was lifted on Wednesday, tens of thousands of people in the city, the origin point and epicentre for the coronavirus pandemic, began travelling out by road, rail and air.China on Thursday released a new trial protocol on recovered Covid-19 patients' quarantine which included return visits by doctors, re-testing and their health monitoring.As of Wednesday, China has 77,370 people who had been discharged after recovery, most of them were from Wuhan and Hubei province which bore the brunt of the virus.According to the protocol, recovered Covid-19 patients should stay in quarantine for 14 days either at home or in an isolation centre for medical observation, the state-run Xinhua news agency reported.During the isolation period, those having recovered from the disease should take their temperatures daily and be on the lookout for fever and respiratory symptoms including cough and breathing difficulties, the protocol said.Designated hospitals should make plans for patients' return visits and re-testing for the next two to four weeks following their discharge, it said, adding that sputum samples are more reliable and should be the first choice for re-testing.Those who have been discharged from hospitals will be categorised as confirmed cases if they test positive, show symptoms including fever and cough, and CT scan results show their lung conditions have worsened. In such cases, the patients should be hospitalised for further treatment, the protocol said.A high-powered committee headed by Chinese Premier Li Keqiang which was leading the efforts to contain the virus since January has also called for intensified detection and prompt response to asymptomatic case meaning people infected with coronavirus but showed no symptoms.As of Wednesday, a total of 1,104 asymptomatic cases, including 364 imported from abroad, were under medical observation on the Chinese mainland, the NHC said.Asymptomatic cases refer to people who are tested positive for the coronavirus but develop no symptoms such as fever, cough or sore throat an official circular said 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 travellers from areas with high risks of infections, it said. The regulation required nationwide hospitals and disease control departments to take prompt actions once asymptomatic carriers are detected.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.Close contacts of asymptomatic cases should also be put under concentrated medical observation for 14 days.Since April 1, the NHC has started to incorporate information on asymptomatic cases in its daily report to timely respond to social concerns.