CHP investigates case of severe paediatric influenza A infection
The Centre for Health Protection (CHP) of the Department of Health is today (September 20) investigating a case of severe paediatric influenza A infection and reminded the community to heighten vigilance against influenza. The 2024/25 Seasonal Influenza Vaccination Programmes will begin on September 26 and the CHP urged the public to receive the seasonal influenza vaccination (SIV) to better protect themselves during the coming influenza season.
The case involves a 9-year-old boy with good past health. He developed a sore throat since September 17 and sought medical attention froma private doctor on the same day. He developed a fever, cough and shortness of breath on September 18 and was brought to Kwong Wah Hospital and was admitted on the same day. He is now at the Paediatric Intensive Care Unit of the hospital for treatment and is now in serious condition. His nasopharyngeal swab specimen was positive for influenza A (H1) virus upon laboratory testing. The clinical diagnosis was influenza A infection complicated with severe pneumonia.
Initial enquiries by the CHP revealed that the patient had no travel history during the incubation period. One of his home contacts is currently symptomatic. The CHP's investigations are ongoing.
A spokesman for the CHP said, "Influenza can cause serious illnesses in high-risk individuals and even healthy persons. SIV is one of the most effective means to prevent seasonal influenza and its complications, as well as reducing influenza-related hospitalisation and death. SIV is recommended for all persons aged 6 months or above except those with known contraindications. Persons at higher risk of getting influenza and its complications, including the elderly and children, should receive SIV early. The 2024/25 Seasonal Influenza Vaccination Programmes will begin on September 26. As it takes about two weeks to develop antibodies, members of the public are advised to receive SIV early for protection against seasonal influenza. Please see details of the vaccination schemes on theCHP's website.
A person who gets influenza and COVID-19 at the same time may be more seriously ill and would have a higher risk of death. It is important to receive both SIV and COVID-19 vaccination as soon as possible, in particular for children and elderly persons residing in the community or residential care homes. The public should also maintain good personal and environmental hygiene against influenza and other respiratory illnesses, and note the following:
- Surgical masks can prevent transmission of respiratory viruses from ill persons. It is essential for persons who are symptomatic (even if having mild symptoms) to wear a surgical mask;
- For high-risk persons (e.g. persons with underlying medical conditions or persons who are immunocompromised), wear a surgical mask when visiting public places. The public should also wear a surgical mask when taking public transport or staying in crowded places. It is important to wear a mask properly, including performing hand hygiene before wearing and after removing a mask;
- Avoid touching one's eyes, mouth and nose;
- Wash hands with liquid soap and water properly whenever possibly contaminated;
- When hands are not visibly soiled, clean them with 70 to 80 per cent alcohol-based handrub;
- Cover the mouth and nose with tissue paper when sneezing or coughing. Dispose of soiled tissue paper properly into a lidded rubbish bin, and wash hands thoroughly afterwards;
- Maintain good indoor ventilation;
- When having respiratory symptoms, wear a surgical mask, refrain from work or attending classes at school, avoid going to crowded places and seek medical advice promptly; and
- Maintain a balanced diet, perform physical activity regularly, take adequate rest, do not smoke and avoid overstress.
The public may visit the CHP'sinfluenza pageand weeklyCOVID-19 & Flu Expressfor more information.
Update on chikungunya fever
The Centre for Health Protection (CHP) of the Department of Health announced that, as of 5pm today (January 11), no new cases of chikungunya fever (CF) had been recorded.
Latest surveillance data
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Hong Kong has recorded a total of 82 confirmed CF cases last year. Among them, 11 were local cases, and the rest were imported cases.
Since the beginning of 2025, and as of December 10, 2025, a total of 502 264 CF cases and 186 CF-related deaths have been reported in over 40 countries/territories. Cases have been reported in the Americas, Africa, Asia, and Europe. Although the northern hemisphere has entered the winter season, temperatures in subtropical and some temperate regions remain elevated due to climate change, creating favourable conditions for mosquito breeding. In addition, CF outbreaks continue to occur in many countries worldwide. The risk of imported cases persists. Members of the public should check the situation of the destinations before travelling abroad, especially when travelling to Southeast Asian countries.
Government's comprehensive follow-up actions
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Given that some local cases of CF have visited the Tsing Yi Nature Trails or the surrounding area in November last year, the trails are currently closed until further notice. Relevant government departments continue to conduct large-scale mosquito control and prevention efforts along the trails, and the CHP appeals to the public not to enter the area in order to reduce the risk of contracting CF and to avoid exposure to chemicals or interfering with the mosquito control operations. Since the confirmation on December 10, 2025, of a case involving a person who had visited the Tsing Yi Nature Trails on November 30, 2025, no further local cases have been recorded to date. The CHP continues to urge individuals who have recently hiked along the Tsing Yi Nature Trails to seek medical attention as soon as possible if they develop relevant symptoms and to call the enquiry hotline (Tel: 2125 2373), which operates from 9am to 6pm.
The Food and Environmental Hygiene Department (FEHD) has been continuously conducting intensive fogging operations to eliminate adult mosquitoes along the Tsing Yi Nature Trails and the surrounding area. At suitable locations, large ultra-low volume foggers have been deployed, and a robot dog is being put on trial to enhance operational effectiveness. The FEHD has also set up new mosquito trapping devices, cleared discarded containers and garbage that could cause stagnant water, and applied larvicide oil or larvicides in areas with stagnant water that cannot be removed immediately. The FEHD has been collaborating with the Kwai Tsing District Office, the Lands Department and the Drainage Services Department to strengthen efforts in eliminating potential mosquito breeding sites along the Tsing Yi Nature Trails. Pamphlets have been distributed to hikers in the area, urging citizens to be vigilant against mosquito infestations and take personal protective measures. The FEHD has also held meetings of the interdepartmental task forces on anti-mosquito work across districts to discuss the latest developments regarding the situation and plan accordingly to co-ordinate relevant departments and stakeholders in strengthening mosquito prevention and control measures in areas under their purview.
Continuously strengthening prevention and control
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The FEHD and relevant departments have comprehensively enhanced the mosquito control operations in Hong Kong since July last year, and this has continued. Among these, the FEHD has conducted vector investigations and targeted mosquito control operations against the imported and local cases. In light of the local case, the FEHD has immediately conducted follow-up actions, including:
carrying out intensive fogging in scrubby areas within a 250-metre radius of the relevant locations to kill adult mosquitoes;
carrying out inspections of the locations, removing stagnant water, applying insecticides and disposing of abandoned water containers every week with a view to preventing mosquito breeding; and
enhancing public education efforts through organising health talks, setting up mobile education stations, and distributing publicity leaflets.
The abovementioned measures will be continued. Furthermore, the Government will further enhance the mosquito control efforts in addition to the existing measures.
Preventive measures to be taken by the public
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Members of the public should use DEET-containing insect repellents or other effective active ingredients properly to prevent mosquito bites, but the following precautions should be taken when using them:
read the label instructions carefully first;
apply right before entering an area with a risk of mosquito bites;
apply on exposed skin and clothing;
use DEET of up to 30 per cent for pregnant women and up to 10 per cent for children (for children who travel to countries or areas where mosquito-borne diseases are endemic or epidemic and where exposure is likely, those aged 2 months or above can use DEET-containing insect repellents with a DEET concentration of up to 30 per cent);
apply sunscreen first, then insect repellent;
reapply only when needed and follow the instructions; and
in addition to DEET, there are other insect repellents available on the market containing different active ingredients, such as IR3535 and picaridin. When using any insect repellent, the public should follow the usage instructions and precautions on the product label.
The FEHD also appeals to members of the public to continue to stay alert and work together to carry out mosquito prevention and control measures early, including inspecting their homes and surroundings to remove potential breeding grounds, changing water in vases and scrubbing their inner surfaces, removing water in saucers under potted plants at least once a week, and properly disposing of containers such as empty cans and lunch boxes. The FEHD also advises members of the public and property management agencies to keep drains free of blockage and level all defective ground surfaces to prevent the accumulation of water. They should also scrub all drains and surface sewers with an alkaline detergent at least once a week to remove any mosquito eggs.
The public should call 1823 in case of mosquito problems, and may visit the following pages for more information: the CF page of theCHPand theTravel Health Service, the latestTravel Health News,tips for using insect repellents, and the CHPFacebook Page,Instagram AccountandYouTube Channel, and also theMosquito Prevention and Control dedicated pageof the FEHD.
Source: AI-found images
