Delta variant identified in Nanjing's COVID-19 clusters

The virus strain behind the latest clusters of COVID-19 cases in Nanjing, capital of east China's Jiangsu Province, has been identified as the highly infectious Delta variant, local authorities said Tuesday.

The recent spike in infections in the city can be attributed to the special location of the outbreak and the highly contagious nature of the strain, said Ding Jie, vice director of the city's center for disease control and prevention, at a press conference.

Nanjing, a mega-city with a population of more than 9.3 million, has added more than 100 locally transmitted COVID-19 cases since a few airport workers tested positive for coronavirus last week.

Ding confirmed that the latest outbreak first emerged among airplane cabin cleaners of the Nanjing Lukou International Airport. The virus has since spread through their work environment and social activities.

On Monday, the Chinese mainland reported 31 new locally transmitted COVID-19 cases, all in Nanjing.

So far, the virus cluster in Nanjing has involved airport workers and their contacts, but new infections were also reported among flight passengers in other parts of China who have visited the Nanjing airport.

South China's Guangdong Province last Thursday reported a new locally transmitted asymptomatic carrier, a flight passenger returning from Nanjing.

Sichuan Province in southwest China on Saturday also reported a confirmed COVID-19 case in the city of Mianyang, after it launched mass testing among travelers from Nanjing.

On Monday, northeast China's Liaoning Province reported three asymptomatic cases in the city of Dalian, who had transited via the airport and spent around two hours there.

Nanjing Lukou International Airport is a busy airport that handled more than 30 million passengers in 2019.

The city of Nanjing has launched its second all-inclusive nucleic acid testing campaign and urged residents not to leave the city unless necessary.

On Tuesday, 11 villages and residential compounds in Nanjing were added to the list of medium-risk areas for COVID-19. The city now has four high-risk areas and 36 medium-risk areas.