The boy, who had good past health and received the 2025-26 seasonal influenza vaccination, first developed a cough and runny nose in late July, followed by a fever on Saturday.
He was admitted to Princess Margaret Hospital and placed under intensive care on Monday after his condition worsened.
The Centre for Health Protection reminded members of the public to maintain strict personal and environmental hygiene, noting that Hong Kong is currently in the flu season, and influenza activity is expected to remain at a high level over the next few weeks.
It added that high-risk individuals such as children, the elderly and those with chronic illnesses should wear surgical masks when using public transport or visiting crowded places.
Parents are also urged to monitor children with influenza closely, and should they notice any worsening symptoms – such as shortness of breath, wheezing, blue lips, chest pain, confusion, a persistent fever or convulsions – they must seek immediate medical attention.
