The Centre for Health Protection today announced that Hong Kong has entered the winter influenza season.

It said that the percentage of respiratory specimens that tested positive for seasonal influenza viruses reached 11.77% during the week ending January 6.

The influenza admission rate in public hospitals also increased to 0.68 cases per 10,000 people last week.

Both figures exceeded the baseline thresholds, the centre noted.

It has written to schools urging them to guard against influenza-like illness outbreaks. Letters will also be sent to doctors, hospitals and institutions calling for heightened vigilance and appropriate actions to fight against influenza together.

The centre reminded the public - especially the higher-risk groups, such as the elderly and children - to get vaccinated for the influenza season.

It also urged people with respiratory symptoms, even if mild, to wear a surgical mask, refrain from work or attending classes at school, and seek medical advice promptly to lower the risk of transmission.

Click here for the latest information on influenza activity.