The recent COVID-19 rebound in southeast China's Fujian Province has been brought under control, while the latest flare-up in the country's northeastern Heilongjiang Province is at a critical stage, a health official said Wednesday.

Continuous efforts should be made to prevent COVID-19 resurgence and contain the further spread of the virus, Mi Feng, spokesperson for the National Health Commission (NHC), told a press conference in Beijing.

The COVID-19 pandemic is still ravaging across the globe, with the Delta variant being the dominant strain. In recent months, China has seen a number of cluster infections caused by imported cases.

Starting from early September, fresh coronavirus cases had been found in several cities in Fujian. As of Tuesday, a total of 470 cases were reported in the province. Thanks to the swift actions by local government and expert team sent by the NHC, the outbreak has been basically put under control, said Cui Gang, an official from the Disease Control and Prevention Department of the NHC.

Since last week, new cases were detected in Heilongjiang. The province reported 75 cases as of Tuesday and is still at a critical stage of fighting against the virus, according to Cui.

As China's week-long National Day holiday and cold weather are around the corner, experts stressed that epidemic control and prevention efforts should not be relaxed.

Over 2.2 billion COVID-19 vaccine doses administered in China

More than 2.206 billion doses of COVID-19 vaccines have been administered across the Chinese mainland as of Tuesday, data from the NHC showed.

More than 1.04 billion people have been fully inoculated against the virus, which is about 74 percent of the country's total population.

China aims to achieve herd immunity by the end of this year. The country's top respiratory expert Zhong Nanshan has said that more than 80 percent of the total population needs be vaccinated to achieve that goal.

Some vulnerable groups have received a booster shot

Wang Huaqing, chief expert on the immunization program at the Chinese Center for Disease Control and Prevention, confirmed that some vulnerable groups have received a booster vaccine dose six months after full-course vaccinations.

He said experts advise three groups of people take a booster shot: people with weakened immune functions and seniors aged over 60; staff working at high risk areas from imported cases, such as medical staff, those employed in airports and customs; and people who have to travel overseas for work or study.

But further study and evaluation of the epidemic development is needed before a decision can be made on whether the entire population needs an extra dose, he said.