Reading the article I understood it like this. ~10 million residents from Wuhan (almost same size as Swedish population) got screened for covid. In ~30k people

Reading the article I understood it like this. ~10 million residents from Wuhan (almost same size as Swedish population) got screened for covid. In ~30k people who recovered from covid, 107 tested positive for covid a second time. Roughly ~1000 people were in contact with asymptomatic carriers, but none (as in 0) tested positive for covid.