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Sentinel Surveillance of Infectious Diseases at Child Care Centres/Kindergartens(CCC/KG)

Sentinel Surveillance of Infectious Diseases at Child Care Centres/Kindergartens(CCC/KG)

The Centre for Health Protection (CHP) of the Department of Health (DH) has established several surveillance systems in Hong Kong to monitor communicable disease activity at the community and public and private healthcare facilities.  With the participation of different partners, CHP will have a more comprehensive picture of the situation of communicable diseases.  The sentinel surveillance system based at CCC/KG is one of the surveillance systems.

This weekly update outlines the data provided by CCC/KG participating in the "Sentinel Surveillance of Infectious Diseases at Child Care Centres/Kindergartens". This update aims at informing the public of community-wide trends of infectious disease based on inference from the collected data, and does not represent the situation at any particular CCC/KG or geographic area.

I. Weekly Overview

Week 22 (29/5 – 2/6)
According to the recent data reported by sentinel CCC/KGs:
- The activities of fever, cough and vomiting were at high levels;
- The activities of hand, foot and mouth disease and diarrhoea have increased.

Year 2023 Week 22 Week 21 Week 20 Week 19
Surveillance period 29/5 - 2/6 22/5 - 26/5 15/5 - 19/5 8/5 - 12/5
Number of children (CCC/KG) under surveillance 17333(92) 14661(89) 15660(91) 17490(97)
a) Surveillance of Symptoms
Percentage of CCC/KG with children affected by fever 59.78 62.92 64.84 60.82
Percentage of CCC/KG with children affected by cough 71.74 71.91 74.73 71.13
Percentage of CCC/KG with children affected by diarrhoea 15.22 12.36 14.29 11.34
Percentage of CCC/KG with children affected by vomiting 15.22 17.98 10.99 12.37
b) Surveillance of Hand, Foot and Mouth Disease
Percentage of CCC/KG with HFMD cases 5.43 4.49 4.40 2.06
c) Surveillance of Absenteeism due to Sickness
Average rate of absenteeism due to sickness 5.23 5.91 5.87 6.07

Remarks: The CHP of DH monitors the overall activity of common infectious diseases through a series of surveillance systems. Overall, the latest surveillance data showed that the activity of hand, foot and mouth disease was at baseline level. The activity of acute gastroenteritis has increased, while the overall local influenza activity has returned to baseline level.

II. Surveillance of symptoms

1) Fever
Weekly chart for occurrence of fever in sentinel CCC/KG, 2022-2023. The activity of fever in week 22 was at high level.

2) Cough
Weekly chart for occurrence of cough in sentinel CCC/KG, 2022-2023. The activity of cough in week 22 was at high level.

3) Diarrhoea
Weekly chart for occurrence of diarrhoea in sentinel CCC/KG, 2022-2023. The activity of diarrhoea in week 22 has increased.

4) Vomiting
Weekly chart for occurrence of vomiting in sentinel CCC/KG, 2022-2023. The activity of vomiting in week 22 was at high level.

III. Surveillance of Hand, Foot and Mouth Disease

Weekly chart for surveillance of hand, foot and mouth disease in sentinel CCC/KG, 2022-2023. The activity of hand, foot and mouth disease in week 22 has increased.

IV. Surveillance of Absenteeism due to Sickness

Weekly chart for surveillance of absenteeism due to sickness in sentinel CCC/KG, 2022-2023. The average rate of absenteeism due to sickness in week 22 was 5.23%.

Methodology

  1. On each operating day, sentinel CCC/KG record the number of absentees due to sickness (data is not collected on days when a CCC/KG is closed due to public holiday, bad weather or other reasons). The total number of absentees due to sickness among all sentinel CCC/KG is divided against the total number of children in attendance to get the gross daily rate of absenteeism. The rates for each day of the week are then averaged to get the week's "Average rate of absenteeism due to sickness".
  2. In each week, sentinel CCC/KG record the presence of cases of Hand, Foot and Mouth Disease (HFMD). CHP calculates the total number of CCC/KG with cases of HFMD, and based on the total number of CCC/KG submitting reports, works out the "Percentage of CCC/KG with cases of HFMD".
  3. Every Wednesday, sentinel CCC/KG record the number of absentees who are showing symptoms of fever, cough, diarrhoea and vomiting. The numbers are reported to CHP at the end of the week (data is collected on the next operating day when a CCC/KG is closed due to public holiday, bad weather or other reasons). Based on the submitted data, CHP works out the "Percentage of CCC/KG with children affected by symptom" for the week.