China's COVID-19 vaccines can provide protection against different novel coronavirus mutations, Shao Yiming, a researcher at the Chinese Center for Disease Control and Prevention, said on Saturday.

It is normal to have breakthrough infections - people who test positive after being fully immunized - because no vaccine is 100 percent capable of preventing people from catching the virus, he said.

In the trial of more than 10 million people, China's CoronaVac COVID-19 vaccine effectively prevented COVID-19 infections in Chile, where most of the infections were from the Gamma strain, he said at a news conference.

Among those who were fully immunized, the vaccine's effectiveness was 65 percent for the general prevention of COVID-19 or minor illness, 87.5 percent for the prevention of severe illness, 90.3 percent for the prevention of ICU hospitalization, and 86.3 percent for the prevention of COVID-19-related death, he said.

Some countries with a high vaccine inoculation rate still have experienced a relapse of the COVID-19 epidemic after the control measures were relaxed, which has shown that strict containment measures should still be implemented after vaccination, he added.