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Respiratory Syncytial Virus Infection

Respiratory Syncytial Virus Infection

22 December 2023

Causative agent

This infection is caused by respiratory syncytial virus (RSV), a single stranded RNA virus. RSV infection occurs throughout the year in Hong Kong.

Clinical features

RSV causes respiratory tract diseases such as infection of the airway, lungs and middle ear. It is the most common cause of bronchiolitis and pneumonia for those under 1 year of age. Patients develop fever and other symptoms such as runny nose, cough, headache, decreased appetite, body ache or weakness, and occasionally otitis media.

Mode of transmission

The virus can be transmitted by direct contact with infectious secretions, by droplets spread, or indirectly through contaminated hands, eating utensils or articles freshly soiled by nasal or throat discharges of an infected person.

Incubation period

The incubation period is 1 – 10 days, usually 5 – 7 days.


The infection usually subsides in about 1 – 2 weeks. Most cases are mild and patients can be managed with supportive treatment. Severe cases may need oxygen therapy and tube feeding. Antiviral agent may be considered for patients with congenital heart or lung diseases. Antibiotics may be needed only if there are bacterial complications such as pneumonia, sinusitis or otitis media.


The best preventive measures are to maintain good personal and environmental hygiene.

1. Maintain good personal hygiene
  • The wearing of mask is advised for the following situations - 
    • any persons with fever or respiratory symptoms;
    • any persons who are visiting or working in high risk places such as residential care homes for the elderly, residential care homes for persons with disabilities, and clinical areas of healthcare facilities; and
    • high risk persons (e.g. persons with underlying medical conditions or persons who are immunocompromised) who are going to crowded places such as public transport.
    • When an increasing trend in activity of respiratory viruses is expected, high risk persons are recommended to wear a surgical mask when visiting public places, while the public should also wear a surgical mask when taking public transportations or staying at crowded places.
  • It is important to wear a mask properly, including hand hygiene before wearing and after removing a mask. For details on proper mask wearing, please visit CHP website at;
  • Perform hand hygiene frequently, especially before touching one’s mouth, nose or eyes; before eating; after using the toilet; after touching public installations such as handrails or door knobs; or when hands are contaminated by respiratory secretion after coughing or sneezing.
  • Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with a disposable paper towel or hand dryer. If hand washing facilities are not available, or when hands are not visibly soiled, performing hand hygiene with 70 to 80% alcohol-based handrub is an effective alternative.
  • Cover your mouth and nose with tissue paper when sneezing or coughing. Dispose of soiled tissues into a lidded rubbish bin, then wash hands thoroughly.
  • When having respiratory symptoms, wear a surgical mask, refrain from work or attending class at school, avoid going to crowded places and seek medical advice promptly.
  • Build up good body immunity by having a balanced diet, regular exercise, adequate rest, do not smoke and avoid alcohol consumption.
  • Infected persons should avoid contact with children, the elderly or those with weakened immunity.
2. Maintain good environmental hygiene
  • Regularly clean and disinfect frequently touched surfaces such as furniture, toys and commonly shared items with 1 in 99 diluted household bleach (mixing 10 ml of household bleach containing 5.25% sodium hypochlorite with 990 ml of water), leave for 15 - 30 minutes, and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
  • Use absorbent disposable towels to wipe away obvious contaminants such as respiratory secretions, and then disinfect the surface and the neighbouring areas with 1 in 49 diluted household bleach (mixing 10 ml of household bleach containing 5.25% sodium hypochlorite with 490 ml of water), leave for 15 - 30 minutes and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
  • Maintain good indoor ventilation.
  • Avoid going to crowded or poorly ventilated public places; high-risk individuals may consider wearing surgical masks when staying in such places.
  • Clean and disinfect eating and drinking utensils after use can reduce the risk of spread of the disease.