The spread of acute respiratory infections, including influenza, has been trending downward in China, but the nation has not passed the seasonal epidemic and the start of a new school semester could amplify the infection risk, according to a health expert and official data.

"The influenza virus remains the predominant pathogen in circulation and the nation is still in the middle of the flu epidemic season. Nonetheless, the intensity of the virus' spread has subsided," said Peng Zhibin, a researcher at the Chinese Center for Disease Control and Prevention, at a news conference held on Monday by the National Health Commission.

For the week starting on Feb 3, the positivity rate of flu climbed slightly by 1.2 percentage points from the previous week to reach 24.9 percent, and the positivity rates of respiratory syncytial virus, adenovirus and human parainfluenza virus all declined, according to the China CDC.

Data also points to a continuing decline in the positivity rates of respiratory syncytial virus, human parainfluenza virus and Mycoplasma pneumoniae infection, as well as a persistent low level of adenovirus, coronavirus and other respiratory pathogens.

Despite a fall in new infections, the China CDC noted that nursery care institutions and schools could face a heightened risk of infection clusters with the onset of the new semester.

Peng, the China CDC researcher, emphasized that the nation is still in the grip of a seasonal epidemic and suggested that people who have not received a flu vaccine do so in order to reduce the risk of catching infections and prevent severe symptoms.

With rising temperatures and the start of the spring semester, Peng said that campuses will be coping with the increased risk of infectious diseases common in spring such as norovirus infections, measles, hand-foot-mouth disease, chickenpox and meningitis.

"These diseases typically spread through respiratory droplets or close contact," she said.

The researcher also advised students and school staff to receive vaccines for preventable diseases promptly in order to strengthen herd immunity.

Meanwhile, it is important to ensure proper ventilation and maintain a clean indoor environment, she said.

"When dealing with vomit or excrement from students infected with norovirus infections, it is recommended to apply chlorine-based disinfectants on the surface for at least 30 minutes before cleaning them up," Peng said.

"Early detection and handling of infection clusters on campus is of paramount importance," she added.