Residents in Shanghai's risky areas are likely required to continue staying at home even after finishing two rounds of nucleic acid testing to reduce mobility during the city's ongoing massive screening.The next-step COVID-19 control measures will be decided based on the results of the screening and analysis of the infection and transmission risks in key areas, according to Wu Jinglei, director of the Shanghai Health Commission.After the testing, the number of confirmed and asymptomatic cases in each area will be estimated, along with their age, information and epidemiological investigation, Wu told a press briefing on Thursday.