Official: City prioritizes detecting new cases, breaking chain of transmission

A COVID-19 outbreak was in a "rapid development" stage in Xi'an, capital of Shaanxi province, and a second round of citywide nucleic acid testing was launched on Tuesday morning to stem the virus' spread.

Xi'an reported 42 locally transmitted confirmed cases on Monday, making a total of 91 confirmed cases since the outbreak started on Dec 9.

More COVID-19 cases were discovered during testing, indicating community spread was a factor, Liu Feng, director of the Shaanxi Center for Disease Control and Prevention, said on Tuesday. He added that related cases were reported in Shaanxi province's Xianyang and Yan'an, as well as in Dongguan in Guangdong province and Beijing.

The epidemic prevention situation in Xi'an remains critical and complicated and the priority lies in detecting new infections and breaking the chain of transmission, Xi'an Vice-Mayor Xu Mingfei said at a news conference in the city on Tuesday.

Also, one case was reported on Monday in Xianyang.

On Saturday, provincial health officials identified all locally confirmed cases as being the highly transmissible Delta variant, and preliminary research showed that the new wave of infections in Shaanxi was a domestic outbreak resulting from virus carriers arriving from abroad.

Genetic sequencing at the Shaanxi Center for Disease Control and Prevention indicated that the 36 locally transmitted COVID-19 cases closely conformed with the imported cases from a flight from Pakistan on Dec 4, said Liu.

For now, the source of the infection has preliminarily been determined to have been brought to China on the Pakistani flight, on which six out of 180 passengers were confirmed to be infected, Yu Chuanhua, a professor at Wuhan University's School of Public Health, said in an interview with China Central Television News on Monday night.

"But there is still a lack of clear correlation between the various transmission chains in Xi'an, and more COVID-19 cases are likely to be discovered during the nucleic acid testing," he added.

Travelers arriving in and leaving Xi'an by car or bus have been required to show proof of a negative nucleic acid test conducted in the previous 48 hours, the city's transport officials said.

Xi'an Xianyang International Airport issued a notice on Sunday that travel for people from medium- or high-risk areas in the city would be limited and passengers from other areas of the city could leave after showing a certificate of negative nucleic acid testing within 48 hours.

A residential neighborhood and a dormitory of Chang'an University in downtown Xi'an were designated high-risk areas on Sunday, and 13 other areas in downtown Xi'an were reappraised as medium-risk areas for COVID-19, the city's epidemic prevention and control headquarters said.

All kindergartens and primary and secondary schools in the city suspended in-class instruction on Monday and began online classes, the headquarters said.

On Sunday, Vice-Premier Sun Chunlan urged Xi'an to contain the spread of the epidemic as quickly as possible and said that she hoped the current situation would soon substantially improve.

Fourteen other confirmed cases were reported elsewhere on the Chinese mainland－including six in Dongguan, Guangdong province－that were associated with the outbreak in Xi'an, the National Health Commission said in a statement on Tuesday.