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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 48 (24/11 – 28/11)
According to the recent data reported by sentinel CCC/KGs:
- The activity of hand, foot and mouth disease has decreased;
- The activities of fever, cough, diarrhoea and vomiting were at baseline levels.

Year 2025 Week 48 Week 47 Week 46 Week 45
Surveillance period 24/11 - 28/11 17/11 - 21/11 10/11 - 14/11 3/11 - 7/11
Number of children (CCC/KG) under surveillance 12592(81) 11144(77) 12290(80) 12972(81)
a) Surveillance of Symptoms
Percentage of CCC/KG with children affected by fever 41.98 50.65 46.25 56.79
Percentage of CCC/KG with children affected by cough 50.62 54.55 46.25 53.09
Percentage of CCC/KG with children affected by diarrhoea 8.64 10.39 11.25 12.35
Percentage of CCC/KG with children affected by vomiting 12.35 10.39 6.25 8.64
b) Surveillance of Hand, Foot and Mouth Disease
Percentage of CCC/KG with HFMD cases 8.64 12.99 12.50 14.81
c) Surveillance of Absenteeism due to Sickness
Average rate of absenteeism due to sickness 3.07 3.29 2.89 3.01

Remarks: The CHP of DH monitors the overall activity of common infectious diseases through a series of surveillance systems. Surveillance data showed that the local influenza activity has been decreasing gradually since late October but remains above baseline levels. Some surveillance indicators of hand, foot and mouth disease (HFMD) have decreased compared to the preceding week, whereas the overall activity in Hong Kong remained at high level. The overall activity of acute gastroenteritis in Hong Kong was at baseline level.

II. Surveillance of symptoms

1) Fever
Weekly chart for occurrence of fever in sentinel CCC/KG, 2024-2025. The activity of fever in week 48 was at baseline level.

2) Cough
Weekly chart for occurrence of cough in sentinel CCC/KG, 2024-2025. The activity of cough in week 48 was at baseline level.

3) Diarrhoea
Weekly chart for occurrence of diarrhoea in sentinel CCC/KG, 2024-2025. The activity of diarrhoea in week 48 was at baseline level.

4) Vomiting
Weekly chart for occurrence of vomiting in sentinel CCC/KG, 2024-2025. The activity of vomiting in week 48 was at baseline level.

III. Surveillance of Hand, Foot and Mouth Disease

Weekly chart for surveillance of hand, foot and mouth disease in sentinel CCC/KG, 2024-2025. The activity of hand, foot and mouth disease in week 48 has decreased.

IV. Surveillance of Absenteeism due to Sickness

Weekly chart for surveillance of absenteeism due to sickness in sentinel CCC/KG, 2024-2025. The average rate of absenteeism due to sickness in week 48 was 3.07%.

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.