​With the Easter and Ching Ming holidays approaching, the Centre for Health Protection (CHP) of the Department of Health today (March 26) reminded the public to remain vigilant about personal, food and environmental hygiene during grave-sweeping activities, gatherings or outbound travels. The public is also advised to get relevant vaccinations promptly in order to guard against various common or travel-related infectious diseases.  
      
Mosquito-borne diseases
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     As the weather gradually warms up, the environmental conditions become favourable for mosquito breeding. During the Ching Ming Festival, people will spend more time outdoors when visiting cemeteries and columbariums to pay respects. Grave sweepers should take proper precautions against mosquito bites, including wearing loose, light-coloured and long-sleeved tops and trousers as well as using DEET-containing insect repellent on exposed parts of the body and clothing. After paying their respects, grave sweepers should also clean out incense burners and other containers, and remove standing water and trash to prevent mosquitoes from breeding. 
      
     Moreover, mosquito-borne diseases continue to spread in many regions worldwide. Dengue fever is prevalent in many neighbouring tourist destinations. Last year, Indonesia, India and Vietnam each recorded over 120 000 cases, while Malaysia and Thailand each recorded over 50 000 cases. Singapore recorded more than 4 000 cases. Regarding chikungunya fever (CF), from early 2025 to December 10, more than 40 countries/regions worldwide, including those in the Americas, Africa, Asia and Europe, recorded a total of 502 264 CF cases and 186 associated deaths.
      
     Preventing mosquito breeding and avoiding mosquito bites are the best ways to prevent mosquito-borne diseases such as dengue fever and CF. Members of the public planning to travel during the Easter holidays should be aware of the situation of mosquito-borne diseases at their destinations and take proper mosquito prevention measures. Those returning from affected areas should continue to use insect repellent for at least 14 days after arrival in Hong Kong.
 
Acute gastroenteritis, norovirus infection and food poisoning
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     Norovirus can cause acute gastroenteritis (AGE). In general, norovirus is more active during the period from winter to early spring (around December to March). Norovirus is highly contagious and individuals may become infected after being exposed to even a small amount of norovirus. The virus can be transmitted through various means, such as eating contaminated food, contacting the vomit or excreta of infected persons, or contaminated objects. It may lead to a large-scale outbreak.
      
     Between mid-January and February this year, there was a significant increase in cases of norovirus food poisoning linked to the consumption of raw oysters in Hong Kong. Although the number of cases has declined this month, the public should remain vigilant during holiday gatherings and avoid eating raw oysters or undercooked bivalve shellfish as far as possible, particularly pregnant women, young children, the elderly, people with weakened immune systems and those with liver disease, in order to prevent infection.
          
     Apart from food poisoning, norovirus is one of the main causes of AGE. The number of local AGE outbreaks has continued to rise over the past four weeks (from February 22 to March 21), with a total of 24 outbreaks reported in institutions and schools and one on a cruise ship during this period, involving a total of 333 people. According to the CHP's sentinel surveillance data, the AGE activity level remains high in Family Medicine Clinics and private medical practitioner clinics. Although the norovirus activity in neighbouring regions (including Japan and Korea) has decreased compared to the beginning of the year, it remains at a relatively active level overall.
  
     To prevent food poisoning and AGE, apart from maintaining good personal hygiene, all food should be thoroughly washed and cooked before consumption. Before handling or eating food and after using the toilet, members of the public should wash their hands with liquid soap and water, and rub for at least 20 seconds, rinse thoroughly and dry with a disposable towel or hand dryer. Since alcohol is not effective in killing norovirus, alcohol-based handrubs are not a substitute for handwashing with soap and water.
     
Seasonal influenza and COVID-19
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     During long holidays, as cross-boundary travel and gatherings with family and friends become more frequent, the risk of transmission of various respiratory infectious diseases also increases. Regarding seasonal influenza, influenza B proportions have recently increased in many parts of the world. Although local influenza activity remains at a low level, the proportion of influenza B among positive respiratory specimens has surged from around 6 per cent in late January to 50 per cent recently, replacing influenza A (H3) as the predominant circulating seasonal influenza virus circulating in Hong Kong. The CHP cannot rule out that the influenza activity may still fluctuate.
 
     Receiving a seasonal influenza vaccination (SIV) remains the most effective way to prevent seasonal influenza and its complications. Vaccinations also reduce the risk of hospitalisation and death from infection. The public should receive a vaccination as soon as possible regardless of staying locally or planning to travel abroad. All individuals aged 6 months or older, except those with known contraindications, should act promptly if they have not yet received a SIV for this season, including those who contracted influenza in the past few months, in order to safeguard personal health.
 
     Regarding COVID-19, there are generally periodic upsurges in activity level in Hong Kong approximately every six to nine months. As over eight months have passed since the end of last periodic upsurge of COVID-19 activity in late June last year, it cannot be ruled out that Hong Kong may experience another periodic upsurge in the next few months. Members of the public should receive a COVID-19 vaccine in a timely manner to reduce the risk of serious illness and death due to COVID-19. Under the current Government's COVID-19 Vaccination Programme, individuals aged six months or above are eligible for free initial vaccine doses. High-risk priority groups can receive booster doses for free at least six months after the last dose or COVID-19 infection (whichever is later), regardless of the number of doses received previously.
　　
     To prevent respiratory diseases, members of the public should maintain good personal, hand and environmental hygiene at all times. Members of the public with respiratory symptoms, even if the symptoms are mild, should wear a surgical mask, avoid crowded places and seek medical advice promptly. They should maintain hand hygiene before putting on and after removing a mask.
 
Meningococcal infection
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     There has recently been an outbreak of invasive meningococcal infection in Kent, the United Kingdom (UK). As of 12.30pm on March 24 (UK time), there have been at least 22 suspected and confirmed cases, two of whom have died. The cases have primarily affected young people, some of whom being students at the University of Kent, as well as individuals who have visited a local club called "Club Chemistry". According to scientific literature, there is a higher risk of transmission or outbreak of meningococcal infection in crowded settings, including university or staff dormitories.
      
     High-risk individuals, including long-term travellers and those studying abroad, should receive meningococcal vaccinations in a timely manner, per the recommendations by the health authorities in the destination country, in order to safeguard personal health. As the Easter holiday approaches, some overseas students will be returning to Hong Kong. Members of the public who develop symptoms of meningococcal infection, including high fever, severe headache, stiff neck followed by drowsiness, vomiting, fear of bright light, or rash, should seek medical advice as soon as possible. The public should also avoid close contact with patients and maintain good personal hygiene to minimise the risk of infection.
 
Measles
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     Measles outbreaks are currently occurring in many regions around the world. North America (including the United States, Canada and Mexico) and Southeast Asia (including Indonesia, Cambodia and the Philippines) have seen persistent measles outbreaks in recent years due to low vaccination coverage rates. In the first three months of this year, about 1 500 cases have been recorded in the United States, a figure far higher than during the same period last year. In Europe, the number of measles cases in the UK and Italy has increased recently, with 270 and 84 cases recorded respectively since January this year. In Asia, the incidence of measles remains high in the Philippines, Indonesia and Cambodia. Japan has also seen a substantial rise in cases this year, with 100 cases recorded as of March 11, which is higher than in the same period for the past six years. Singapore and Australia have reported 21 and 78 measles cases respectively this year, also higher than in the same period last year. Most of the overseas cases have affected people who were not vaccinated against measles or had an unknown vaccination status, which highlights the importance of maintaining a high vaccination rate and herd immunity within the community.
　
     For those who plan to travel to measles-endemic areas, they should check their vaccination records and medical history as early as possible. If they have not been diagnosed with measles through laboratory tests and have never received two doses of measles vaccine or are not sure if they have received a measles vaccine, they should consult a doctor for vaccination at least two weeks prior to their trip. Pregnant women and women preparing for pregnancy who are not immune to measles or rubella as well as children aged under 1 year who are not due for the first dose of the measles, mumps and rubella combined vaccine under the Hong Kong Childhood Immunisation Programme are advised not to travel to places with outbreaks of measles or rubella. The incubation period of measles is seven to 21 days. Symptoms include fever, skin rash, cough, runny nose and red eyes. If travellers returning from places with high incidence or outbreak of measles develop symptoms of measles, they should wear a surgical mask, stay home from work or school, avoid crowded places and contact with people without immunity, especially those with weak immune systems, pregnant women and children under 1 year old, and seek medical advice immediately.  
 
     Members of the public may visit the DH's Travel Health Service webpage for information on infectious diseases around the world and the precautionary measures.

Ends/Thursday, March 26, 2026
Issued at HKT 14:39

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