A 25-year-old female medical worker at Shanghai Songjiang Central Hospital was recently diagnosed with COVID-19, the city's health authorities said on Wednesday.
Her 10 close contacts have received nucleic tests, all of which were negative, and have been quarantined, said Wu Jinglei, director of the Shanghai Health Commission.
Although she had tested negative during previous every-three-day regular nucleic acid tests since August 2, she tested positive during the most recent test despite being fully vaccinated.
She's reported to have a mild case and has been sent to Shanghai Public Health Center for treatment.
She hadn't left Shanghai in the past 14 days and has no connection with recent COVID-19 outbreaks in other Chinese cities, said Wu.
The Chinese mainland Wednesday reported five new locally transmitted COVID-19 cases, the National Health Commission said in its daily report Thursday.
Among the local cases, three were reported in Jiangsu, and one each in Shanghai and Yunnan.
Also reported were 41 new imported cases, including 11 in Tianjin, 10 in Guangdong, six in Yunnan, five in Shanghai, four in Fujian, and one each in Beijing, Inner Mongolia, Zhejiang, Henan and Sichuan.
No new deaths related to COVID-19 were reported, the commission added.