China's influenza activity has declined for four consecutive weeks and remains at a moderate level, the Chinese Center for Disease Control and Prevention said on Tuesday.

Speaking at a news conference, Xin Li, a researcher at the China CDC, said flu activity has fallen across all provincial-level regions and that the number of clustered infections in schools has dropped for five straight weeks.

Data released by the China CDC on Friday showed that the flu positivity rate for cases of influenza-like illness at sentinel hospitals was 27.4 percent for the week beginning Dec 29.

The second most common pathogen during the period was respiratory syncytial virus, with a positivity rate of 8.8 percent, followed by rhinovirus at 5.7 percent.

Among flu-positive samples, 97.3 percent were identified as the H3N2 subtype of influenza A.

Xin said all detected pathogens are known and common types, with no unknown pathogens or new infectious diseases identified.

"Although flu activity continues to decline, we must not let our guard down," she said.

She added that respiratory syncytial virus infections have intensified recently, with relatively high positivity rates in northern provinces and among children aged 4 and under.

"As there is no vaccine available for the virus, strengthening personal protection remains the most important preventive measure," she said.

Xin said China's flu surveillance network now includes 665 national-level laboratories and 1,041 sentinel hospitals, allowing for real-time monitoring of flu transmission, early detection of viral mutations, and support for vaccination strategies recommended by the World Health Organization.

She cited recent international research showing that flu vaccines can prevent about 67 percent of pediatric hospitalizations, 43 percent of severe cases in children and 48 percent of adult hospitalizations.