23 May 2019

Chickenpox precautionary measures

Dear Parents,

South Island School is committed to maintaining a healthy school environment for everyone, therefore we work very closely with the Department of Health and the Education Bureau to ensure that the school is up-to-date with all the latest government guidelines. Community issues do require a community effort if we are to keep infection at a minimum and have control measures to keep our school safe and healthy.


Health & Safety Guidelines


Chickenpox (varicella) is an acute infectious disease caused by the varicella-zoster virus. It predominantly affects children under 12 years of age. Although almost all persons develop lifelong immunity after a chickenpox infection, the virus may remain latent in the body and recur many years later.


Clinical features

  • Patients usually start with a fever and itchy skin rash.
  • Rashes develop in crops over a period of 5 days on the body, then spread to the face, arms and legs.
  • The rash first appears as flat spots and later as vesicles. The vesicles continue for 3 – 4 days, then dry up and form scabs.
  • Patients usually recover in about 2 – 4 weeks.
  • Persons who have received the chickenpox vaccination may still develop chickenpox.


Mode of transmission

  • Can be spread through droplets or air.
  • Can also spread through direct or indirect contact.


Incubation period

  • 10 – 21 days, usually 14 – 16 days


Infectious period

Usually 1 – 2 days before the rash appears and until all vesicles have dried up. It is extremely contagious, especially in the early stage of rash eruption.



Chickenpox is generally a mild disease and is usually self-limiting. However, secondary bacterial infection of the wound may occur. Those with weakened immunity or who are pregnant are most likely to suffer from severe complications. New-born babies who develop chickenpox can become severely ill and even die. Infection in early pregnancy may be associated with congenital malformation of the foetus.



  • Consult the doctor to understand the condition and follow the health professional’s advice and medication to relieve symptoms.
  • If the patient has fever, drink plenty of water and have adequate rest.
  • Wear clean cotton gloves during sleep to prevent scratching of the vesicles which may cause infection and scarring.
  • Avoid contact with pregnant women and persons with weakened immunity.
  • Sick children should stay at home and be excluded from schools/kindergartens/child care centres until all vesicles have dried up, usually about 1 week after appearance of rashes to prevent spreading the disease to others.
  • Parents should closely monitor the child’s condition. If the child persistently runs a fever, refuses to eat or drink, vomits or looks drowsy, immediate medical attention should be sought.
  • Parents should also closely monitor other children in the household for signs and symptoms of chickenpox.



  • Maintain good personal and environmental hygiene.
  • Chickenpox vaccine is available in Hong Kong. About 90% of persons who receive the vaccine will acquire immunity.
  • Under the Hong Kong Childhood Immunisation Programme, children receive a two-dose course of chickenpox vaccination. Parents may consult family doctors or maternal and child health centres for details.
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