Minimizing impact

Authorities say the highly transmissible Omicron variant of COVID-19 has been found to be the cause of the latest outbreak in the city. Infected people often show no symptoms but can still transmit the virus, according to Wu Jinglei, director of the municipal health commission.

"Health workers have been applying the same quarantine and contact-tracing protocols to asymptomatic patients and their close contacts," he says.

Statistics show that about 80 percent of the new infections in the current outbreak were uncovered during testing of quarantined contacts of previous cases, while the remaining cases were found during testing of people with risks of exposure.

As one of China's busiest transport hubs, Shanghai also faces risks of COVID-19 infection from outside. In the past year, nearly 40 percent of international flights arriving in China landed in Shanghai, and since the start of the pandemic, the city has seen 4,367 imported cases.

As of Wednesday, 643 of the cases were receiving treatment.

As all inbound travelers were subjected to two weeks of quarantine and seven days of self-health monitoring when travel into the city was permitted before the latest outbreak, many hotels had been converted into quarantine facilities. Authorities now say "one of the origins of the current outbreak is a quarantine hotel, which had mismanaged its containment protocol".An investigation team has been formed to look into the incident.

The Civil Aviation Administration of China announced changes on Tuesday. A total of 106 inbound flights to Shanghai from March 21 to May 1 were diverted to 12 airports in other cities, including Chengdu in Sichuan province, Chongqing and Xiamen in Fujian province.

"We will prevent and control the spread of COVID-19 proactively, precisely, scientifically and comprehensively, and strive to minimize the impact of the pandemic on the normal lives of residents," Gu says. "We did not initiate a city (Shanghai) lockdown and presently it's not necessary to apply the measure."