CHP investigates two severe paediatric influenza infection cases
The Centre for Health Protection (CHP) of the Department of Health (DH) is today (May 20) investigating two paediatric cases with developments of severe complications following infection with seasonal influenza. The cases involve two boys with good past health. The CHP reiterated that the seasonal influenza vaccination (SIV) is one of the most effective methods of preventing influenza and its complications, and can reduce the risk of serious complications or death from infection.
The first case involves a 12-year-old boy. On May 12, he developed a fever, sore throat, cough, runny nose and malaise. On May 14, he further developed vomiting and confusion. During this period, the patient attended a private doctor. He was taken to the Accident and Emergency Department of Tseung Kwan O Hospital on May 16, where he was hospitalised for treatment. His condition subsequently worsened, and he was transferred to the paediatric intensive care unit of United Christian Hospital on May 18. His respiratory specimen tested positive for influenza B virus upon laboratory testing. His clinical diagnosis is influenza B complicated with encephalopathy. He remains hospitalised and is in critical condition.
The other case involves a 10-year-old boy. On May 10, he developed a fever, cough and runny nose. He attended a private doctor on the following day (May 11). On May 12, he developed shortness of breath and was taken to the Accident and Emergency Department of Pamela Youde Nethersole Eastern Hospital. Due to a drop in blood oxygen levels, he was admitted to the hospital's paediatric intensive care unit with a clinical diagnosis of pneumonia. His respiratory specimen tested positive for influenza A virus upon laboratory testing, while tests for other viruses and bacteria were negative. Based on the clinical data, the CHP considered that the boy developed pneumonia as a complication of influenza A infection. The patient has recovered and has been discharged from the hospital.
Upon receiving notifications of these two cases, the CHP immediately conducted epidemiological investigations. Preliminary results revealed that both boys had received the 2025/26 SIV late last year. Neither of them has a recent travel history.
Although influenza activity in Hong Kong remains at a relatively low level, the percentage of respiratory specimens tested positive for seasonal influenza viruses has increased slightly in the last week. Based on past experience, Hong Kong may experience two influenza seasons each year. Last year's summer influenza season began later than usual and lasted longer than normal, extending from early September to early January, resulting in the absence of the winter influenza season that traditionally occurs in the first quarter of each year. Nearly six months have passed now since the last influenza season. Given that many members of the public have not been infected with the seasonal influenza virus in recent months, it cannot be ruled out that influenza activity may rise again. The CHP once again urges all persons aged 6 months or above, except those with known contraindications, that if they have not yet received an SIV, they can still get vaccinated now.
The CHP also reminded members of the public that, especially for children, the elderly and those with underlying illnesses, they should seek medical advice promptly for early treatment if they present with fever and respiratory symptoms. As children with influenza can deteriorate rapidly, parents must pay close attention to their children's condition. They should go to an Accident and Emergency Department immediately if the child's condition deteriorates, for example, if they develop symptoms such as shortness of breath, wheezing, blue lips, chest pain, confusion, a persistent fever or convulsions.
Separately, high-risk individuals should wear surgical masks when staying in crowded places. People with respiratory symptoms, even if mild, should wear a surgical mask and seek medical advice promptly. They should also consider whether to attend work or school.
Members of the public may refer to the CHP's COVID-19 & Flu Express,Seasonal Influenza Webpage, COVID-19 Vaccination Programme Webpage, and Vaccination Schemes Webpage, for the latest information.
The Centre for Health Protection (CHP), Photo source: reference image
