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Severe Acute Respiratory Syndrome (SARS)

Severe Acute Respiratory Syndrome (SARS)

11 August 2017

Causative agent

Severe acute respiratory syndrome (SARS) is a viral respiratory infection caused by the coronavirus named SARS-coronavirus (SARS-CoV).

Clinical features

The initial symptoms are similar to influenza infection. Patients with SARS usually begin with fever, which is often high (38°C or above), and sometimes associated with chills, rigors, headache, malaise, muscle pain or even diarrhoea. At the onset of illness, some patients may only have mild respiratory symptoms. After a few days, symptoms of lower respiratory tract infection may follow, including cough and difficulty in breathing. In around 10% of patients, the illness may rapidly progress to respiratory failure requiring intensive medical care. Symptoms can be more variable among elderly patients.

Mode of transmission

SARS is predominantly transmitted through close person-to-person contact, especially via respiratory droplets produced when an infected person coughs or sneezes. Droplet spread can take place when droplets from the cough or sneeze of an infected person are propelled a short distance and deposited on the mucous membranes of the mouth, nose, or eyes of persons who are nearby. The virus can also spread when a person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, nose, or eyes.

Incubation period

Symptoms usually appear within 2 – 7 days after contracting the disease, but the incubation period can be up to approximately 10 days.


Treatment is mainly supportive.

There is no vaccine currently available. Good hygiene practice remains the most effective way to minimise the risk of contracting and spreading the disease.


Maintain good personal hygiene

  1. Avoid touching eyes, mouth and nose.
  2. Keep hands clean at all times. Perform hand hygiene frequently, especially:
  • Before touching eyes, mouth and nose;
  • Before handling food or eating;
  • When hands are soiled by faeces, respiratory or other body secretions;
  • After going to the toilet;
  • After touching public installations or equipment, such as escalator handrails, elevator control panels or door knobs.
  1. Wash hands with liquid soap and water and rub hands for at least 20 seconds, and then dry with a disposal paper towel or hand dryer.
  2. When hands are not visibly soiled, clean them with 70 - 80% alcohol-based handrub as an effective alternative.
  3. Cover the nose and mouth with tissue paper when sneezing or coughing. Dispose of soiled tissue into a lidded rubbish bin and then wash hands thoroughly.
  4. People with symptoms of respiratory tract infection or fever should wear a surgical mask and consult a doctor promptly.
  5. Use serving chopsticks and spoons at meal time. Do not share lunch boxes or drinks with others.
  6. Avoid going to crowded or poor ventilated public places if you are feeling unwell. 

Maintain a healthy lifestyle - a balanced diet, regular exercise and adequate rest. Do not smoke.

Maintain good environmental hygiene

  1. Keep home clean. Clean furniture and household facilities with 1 in 99 diluted household bleach (mixing 1 part of 5.25% bleach with 99 parts of water) daily. Then rinse with water and wipe dry. For metallic surface, disinfect with 70% alcohol.
  2. Maintain good ventilation:
  • Keep windows open to maintain good indoor ventilation;
  • Wash dust filters of air-conditioners frequently;
  • Maintain proper function of the air ventilation.
  1. Keep the toilet clean:
  • Clean the toilet at least once daily with 1 in 99 diluted household bleach solution.
  • When using the toilet, it is essential to observe hygienic practices:
    • Dispose of used toilet paper in the toilet bowl;
    • Before flushing, lower the toilet lid to prevent contaminated water from splashing out;
    • Flush the toilet;
    • When flushing has stopped, raise the lid;
    • Ideally, wipe the rim, seat and lid with disinfectant and air dry;
    • Wash hands thoroughly with liquid soap and water. Dry hands with a disposal paper towel or a hand dryer.
  1. Maintain proper function of toilets, drains and pipes:
  • Clean the floor drain outlets regularly;
  • Pour about half a litre of water into each floor drain outlet at least once a week to prevent foul air and insects in the sewage pipe from entering the premises;
  • Make sure drains and pipes do not leak or are not blocked. Do not alter them without prior authorisation. Arrange immediate inspection and repair by qualified technicians if there is a defect in the U-trap or smell of foul air is coming from drain outlets.
  1. Do not spit or litter.
  1. Make sure that common facilities such as staircases, lifts, lobbies, refuse collection chambers, canopies and ventilation fans are cleaned, disinfected and maintained regularly.
  1. Prevent pest infestation - proper storage of food, proper disposal of rubbish, be aware of signs of pest infestation and arrange for pest disinfestations where necessary.