BEIJING — China's experience and protocols in containing the COVID-19 epidemic since last year have been effective in curbing the Delta variant, the National Health Commission (NHC) has said.

Such effectiveness had been proved in the handling of the COVID-19 resurgence that started in July at Nanjing Lukou International Airport, East China's Jiangsu province, the NHC said.

The resurgence was triggered mainly by the highly contagious Delta variant and turned out to be one of the worst COVID-19 outbreaks in China.

The epidemic in the country has been eased, and the risk of national-level outbreak decreased, the NHC noted.

Review and optimization are needed to improve existing protocols, it added.

Measures against imported infections will be tightened, said Wu Liangyou, deputy head of the NHC's disease control and prevention division.

Containment will be strengthened at crucial places and emergency handling capability improved, he said.