Traditional Chinese medicine doctors distribute packages of herbs to workers at a machine factory in Fuzhou, East China's Jiangxi Province on Tuesday. The herbs will help strengthen workers' immunity after they returned to work. Photo: cnsphoto

At least 12 collective coronavirus cases have been confirmed in companies after employees returned to work across China, with 15 confirmed infections among employees and over 514 being quarantined, according to media reports.

On February 8, a suspected case was found at a power plant in North China's Shanxi Province and 26 people who have close contact with the worker have been quarantined, and the plant is on lockdown. 

Beijing-based online bookstore Dangdang reported a confirmed coronavirus case on Thursday, resulting in 66 people being quarantined, Zhang Yanlin, duputy director of the Beijing Municipal Commission of Development and Reform, said at a press conference on Saturday.

Zhang said the commission has talked with Dangdang's head and asked the company to make instant rectifications.

Hangzhou, capital of East China's Zhejiang Province held a press conference on Friday, stressing that businesses that have resumed operations should check workers' health every day and instantly quarantine the employees and report when an employee has symptoms of a fever, cough or other abnormal symptoms.

Currently, companies and factories across China, especially in regions hit less hard by the virus, are ramping up business operations. South China's Guangdong Province - an important manufacturing hub - saw that 65 percent of industrial and commercial companies in the province have reopened by Friday, according to the province's press conference held Saturday.