A seven-year-old boy died due to flu after his condition rapidly deteriorated on Tuesday, the first fatal case of pediatric influenza infection in Hong Kong this year, according to the Centre for Health Protection.

The CHP urged members of the public to maintain strict personal and environmental hygiene as the level of influenza activity is expected to remain high in the coming weeks after the city entered the flu season in late June.

“The health condition of children with influenza can deteriorate rapidly,” the CHP said in a statement on Tuesday.

“Parents must pay close attention to their condition, and visit an accident and emergency department immediately if the child's condition deteriorates with symptoms such as shortness of breath, wheezing, blue lips, chest pain, confusion, a persistent fever or convulsions.”

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The boy had developed a cough and runny nose on July 27, and a fever on Saturday, before his condition deteriorated on Monday, with decreased responsiveness.

He was taken to the Accident and Emergency Department of Princess Margaret Hospital and was admitted to the pediatric intensive care unit. His clinical diagnosis was influenza A infection complicated with shock and encephalopathy.

The CHP's preliminary investigation revealed that the boy had received the 2025/26 seasonal influenza vaccination and had had no travel history during the incubation period.

One of his household contacts recently developed upper respiratory symptoms and tested positive for influenza virus via a rapid antigen test. However, the household contact's condition was mild and did not require hospitalization.

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Controller of the CHP Edwin Tsui Lok-kin said on Monday that the latest surveillance data revealed that the percentage of respiratory specimens testing positive for seasonal influenza viruses was 10.65 percent and the influenza admission rate in public hospitals was 0.67 cases per 10,000 population last week.

“Both indicators increased last week,” Tsui said. “We expect the level of influenza activity to remain high in the coming weeks."