China's flu activity is expected to peak in early to mid-December, Wang Dayan, a researcher at the Chinese Center for Disease Control and Prevention said during a news conference on Friday.

A total of 17 provincial-level regions are currently reporting high flu activity, while the rest are at medium levels, Wang added.

The positivity rate for flu among patients with flu-like symptoms has reached 51 percent, though it remains below the highest levels recorded over the past three years.

Reports of clustered infections in schools continue to rise, with the detection rate among children aged 5 to 14 significantly higher than in other age groups.

The H3N2 subtype of influenza A remains dominant, accounting for more than 95 percent of cases, while small numbers of the H1N1 subtype of influenza A and influenza B cases have also been detected.