Seniors and people identified as being at higher risk from COVID-19 are now eligible for a second vaccine booster shot, according to a notice issued on Wednesday.

The booster can be administered to people age 60 and above, those who have already received a booster shot and are at high risk of infection, those with serious underlying conditions and those with low immunity, said the notice released by the joint prevention and control mechanism of the State Council.

All vaccines with conditional approval for market or emergency use can be used for the second booster.

People are also advised to get a different variety of vaccine from the original one they were inoculated with or Omicron-resistant vaccines for their second booster, which should be administered at least six months after the first booster.

Health authorities must make vaccine safety their top priority and ensure vaccinations are done in a standardized, safe way, the notice said.

The second booster inoculation program should be conducted in an orderly way, with emergency response plans at vaccination sites and updated inoculation information available, it added.

Xia Gang, director of the department of health and immunization at the National Administration of Disease Prevention and Control, said that as of Tuesday, the Chinese mainland has administered more than 3.45 billion doses of COVID-19 vaccines, and more than 1.37 billion people have received at least one vaccination shot.

A total of 1.27 billion people have been fully vaccinated with two shots, and 815.7 million people have received a booster shot, he said at a news conference on Wednesday.

A total of 240 million seniors, or about 91 percent of those age 60 and above, have received at least one dose, while 228.6 million have been fully vaccinated with two shots and 184 million have received a booster shot, he said.

People age 60 and above, especially those 80 and older, who have underlying conditions are more likely to suffer from serious or even critical conditions if they are infected with COVID-19, so they benefit the most from getting vaccinated, Xia said.

Seniors who may have a severe allergic reaction should not get a COVID-19 vaccination. Older people who are in an acute stage of chronic disease or have fever due to an infectious disease should also hold off vaccination until they are better, Xia said.

Local authorities have made sure that vaccination sites are equipped with emergency response personnel, equipment, medicine and ambulances to help seniors get vaccinated soon, he added.