China's flu season is underway, with cases increasing rapidly across the country and expected to continue rising in the coming weeks, health authorities said recently.

Latest data released by the Chinese Center for Disease Control and Prevention shows that the flu positivity rate among all influenza-like illnesses tested at sentinel hospitals rose to nearly 45 percent for the week starting on Nov 17, up from about 38 percent the previous week.

The China CDC said the overall flu epidemic is at a medium level, with some provinces already registering high flu activity.

"The number of infection clusters detected at schools has continued to increase, and the positivity rate among those aged five to 14 is significantly higher than other age groups," it added.

Other viruses in circulation include rhinovirus, respiratory syncytial virus, and enterovirus. Their spread is trending downward but remains at a noticeable level.

The China CDC suggests nursery care homes, schools, and elderly care facilities carry out health monitoring and deal with infection clusters promptly.

The public, especially medical staff, the elderly, and those with preexisting illnesses, are advised to take vaccinations and wear masks in public spaces.