Thousands tested

On Monday, video clips of nucleic acid tests being administered to more than 17,700 cargo workers at Pudong International Airport the previous night went viral.

The tests involved 240 doctors and nurses and 300 workers who helped with preparatory work.

Netizen Xin Zhidu said: "The tests were like a meticulous blanket search for a suspicious infection. We're confident the city, which has a government that people trust, will make it through. Stay strong Shanghai and the world!" The comment received 27,000 "likes".

Epidemiologists said the infections among the airport workers are a reminder that imported non-cold-chain cargo may become a viral transmission route in winter.

Zhou Junlong, vice-president of the Shanghai Airport Authority, said strict cargo disinfection, standard loading and unloading procedures and protection for key workers will be strengthened at cargo handling facilities.

Pan Hao, deputy head of Shanghai's front-line COVID-19 work team, said epidemiological investigation tracing for the cases reported in the past week was expanded from close contacts, and those linked to them, to individuals at the same work site or in the same occupation.

A case reported on Monday was discovered among the nucleic acid test results for the airport cargo workers.