A student receives a dose of COVID-19 vaccine at a vaccination point of Wenshu middle school in Nanjing, east China's Jiangsu Province, Aug. 23, 2021. Nanjing started administering the first dose of COVID-19 vaccines among minors aged between 12 and 17. (Xinhua/Ji Chunpeng)

 Some cities in China have introduced policies requiring COVID-19 vaccination record checks at international fairs and entrances of public transport facilities as China continues to strengthen epidemic prevention against variants and advance the vaccination pace. 

The Beijing Center of Disease Control and Prevention announced on Sunday that people who are not fully vaccinated, "in principle," will not be allowed to participate in the China International Fair for Trade in Services, the largest and richest first-class exhibition in global services trade, which is to be held in Beijing from September 2 to 7.

The regulations were imposed to ensure the safety of the participants, especially when the Delta variant has become the most prevalent strain in recent outbreaks, said Liu Xiaofeng, a deputy director of the Beijing CDC, at a press conference on Sunday.

But Liu noted that guests at the fair could provide nucleic acid testing certificates taken within 24 or 48 hours if they are not vaccinated.

The fair will also extend the investigation timeframe of participants' epidemiological history from 14 days to 21 days, and those with a risk of infection will not be allowed to attend the event.

On Sunday, the subway system in Changsha, Central China's Hunan Province, announced it would start requiring passengers to show COVID-19 vaccination records before entering stations. 

According to a notice that Changsha Metro posted on WeChat, passengers need to provide both their health QR codes and COVID-19 vaccination records at the entrance, starting from Sunday. 

Those who are not vaccinated can enter the station after filling in a questionnaire asking their personal information including name, phone number, ID number, home address and reasons for not getting vaccinated. 

Dalian, Northeast China's Liaoning Province, introduced a similar policy for airport passengers on Saturday. An airport staffer said that no notification has been made forbidding passengers without vaccination records to enter the terminal buildings, but they suggested that people "get the shot as soon as possible," reported the Beijing News. 

Senior people who were not vaccinated for  physical reasons could present a medical note from their doctors to explain their situation to the airport staff, said the report.

China had administered more than 2 billion doses of COVID-19 vaccines as of Saturday. 

The country has effectively controlled the outbreaks that started in July in various parts of the nation, said a State Council press conference on Friday. A vaccine research and development expert said that COVID-19 vaccines contributed to the country's battle in controlling the outbreak.