SARI - Severe Acute Respiratory Infection surveillance by a sentinel network of hospitals

Last updated on 17-4-2024 by Cassandre Dugailliez
Project duration:
January 1, 2012
Project with no end date

In short

Sciensano coordinates a surveillance network of ten hospitals that records all cases of Severe Acute Respiratory Infections (SARI). This surveillance aims to detect signs of increased severity of seasonal influenza and other acute respiratory infections in good time, and to report them to the health authorities (both nationally and internationally to the ECDC and WHO). In addition, the germs responsible and their characteristics are studied.

Project description

A comprehensive surveillance system for influenza and other acute respiratory infections has been set up at national and European level. In Belgium, sentinel networks, coordinated by Sciensano, monitor the number of new acute respiratory infections in different healthcare institutions on a weekly basis. Hospital admissions for acute respiratory infections are monitored as part of the Severe Acute Respiratory Infections (SARI) surveillance program by a network of sentinel hospitals.

An admission for SARI is defined as:

until 12 November 2023:

  • a hospital admission of at least 24 hours,
  • for severe symptoms of acute respiratory infection, defined as fever (≥ 38°C) and (cough and/or shortness of breath)
  • which occurred suddenly (in the last 10 days before admission),
  • in which nosocomial infections are excluded.


from 13 November 2023 on:

  • A hospital admission of at least 24 hours,
  • for at least 2 of the following signs of respiratory tract infection:

o fever ≥ 38°C (measured in hospital) or history of fever,

o cough,

o signs of respiratory distress (including but not limited to dyspnoea),

o abnormal auscultation of the lungs

o in children: apnoea or cyanosis

  • that occurred suddenly (in the last 10 days before admission),
  • nosocomial infections excluded.

Since 2012, six and since 2023 ten general hospitals participate in Belgian surveillance of severe acute respiratory infections (SARI). The network covers patients from all Belgian provinces and are all hospitals with high intensive care activity. All hospital departments are involved in the surveillance.

For each SARI hospital admission, hospitals track patients throughout their stay and record various parameters. Information collected includes demographics, symptoms, risk factors and co-morbidities, vaccination status, treatment, severity and outcome of illness. In addition to recording clinical data, a swab sample is also taken from each patient’s throat and/or nose. The sample is tested for respiratory viruses by the National Reference Center for Influenza.

Those responsible for surveillance in the participating hospitals and the involved Sciensano researchers together form the File BELSARI-NET research group

The integrated results of SARI surveillance, together with surveillance using sentinel networks of GPs, laboratories and nursing homes, provide information on:

  • the duration and intensity of annual epidemics of respiratory tract infections
  • the respiratory viruses in circulation
  • the impact and severity of epidemics
  • resistance to antiviral drugs
  • the effectiveness of the flu vaccine.

The results of these surveillances are published every week in the acute respiratory infections bulletin in French or in Dutch 

Information for patients at participating hospitals:

PDF icon Information for adults (EN)

PDF icon Information for children (NL)

PDF icon Information for adults (NL)

PDF icon Information for children (FR)

PDF icon Information for adults (FR)

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