Shanghai has implemented stringent measures to tame a surge in COVID-19 cases, as the city reported 38 local confirmed COVID-19 cases and 2,231 asymptomatic carriers. The eastern Chinese metropolis on Saturday launched a new round of citywide screening, using both nucleic acid and antigen testing in its latest efforts to contain the COVID-19 outbreak. As Shanghai conducts citywide nucleic acid testing and collects a huge number of samples every day, testing staff are under great pressure, even with two shifts per day in the lab. In order to ensure that all residents use antigen detection reagents correctly, many volunteers and community medical workers have been going door to door showing residents how to do the tests properly. Volunteers are also working around the clock to recover antigen detection reagents.