Even though the COVID-19 pandemic is waning, people are still encouraged to get vaccinated and get their booster shots regardless of whether they have been previously infected or not, so as to reinforce herd immunity against the virus, Chinese authorities said on Monday.

At present, the domestic vaccination campaign is focused on bridging the gap in immunity levels across different populations and further reducing the risk of severe cases and deaths, according to a circular released by the State Council's Joint Prevention and Control Mechanism.

That means continuous efforts will be made to fully vaccinate people aged 3 to 17 and ensure that those aged 18 and above get a first booster shot and that vulnerable groups including the elderly and those with severe chronic diseases obtain a second booster shot.

It noted that people recently infected with COVID-19 need only wait three months before getting vaccinated. The previously recommended waiting period was six months.

The continuous optimization of the COVID-19 control strategy since November led to an epidemic wave that peaked in late December and infected at least 80 percent of the total population, according to the Chinese Center for Disease Control and Prevention.

The daily number of positive nucleic acid cases peaked on Dec 22 at 6.94 million and has trended downward falling to around 2,120 on Thursday, according to the latest data released by the China CDC on Saturday.

The daily numbers of hospitalized COVID-19 patients, severe cases and related deaths in hospitals have also fallen continuously since early January. No fatalities linked to COVID-19 have been reported since March 31.

Wu Zunyou, chief epidemiologist at the China CDC, said during a news conference in February that because the immunity gained following exposure to the virus can last for several months, the possibility of another wave of infections in the next few months is small. But he still recommended seniors and other vulnerable populations to take personal protective measures and get vaccinated and booster shots as soon as possible.

In a statement explaining the newly released circular, the National Health Commission said that the novel coronavirus has not vanished and cases have sprouted up in some regions.

"There are also gaps in immunity levels across different populations," it said.

The commission said people who have never had COVID-19 and have not finished recommended immunization courses are still at risk of developing serious symptoms. For those who have been infected but have not completed primary immunization, their immunity level is also significantly lower than those who have been fully vaccinated before getting infected.

"Immunity levels tend to gradually diminish over time, so some people still need to get vaccines so as to strengthen protection against the disease," the commission said.

The commission also strongly recommends getting a different vaccine as a booster shot than the one used for the primary inoculation.

For instance, people vaccinated with two shots of inactivated vaccines are recommended to choose recombinant-protein vaccines or virus-vector vaccines. The first homegrown vaccine based on the messenger RNA technology, which gained emergency authorization last month, is recommended for people aged 18 and above, it said.

As of Thursday, China had fully vaccinated 90.6 percent of its total population, including 230 million people aged 60 and above, according to the China CDC.