ILI-NH - Influenza-like illness (including COVID-19) sentinel surveillance in Belgian nursing homes

Last updated on 11-1-2024 by Milena Callies
Project duration:
October 17, 2022
December 31, 2026

In short

The World Health Organization has recommended to integrate COVID-19 surveillance in a sentinel surveillance for influenza like-illness (ILI). ILI (such as flu and other respiratory infections) and COVID-19 represent a significant burden for the nursing home (NH) population. Hence, a surveillance in this subpopulation is necessary to monitor ILI for alarm signs of sudden rise in cases, hospital admissions and deaths.

Project description

The objective of the study is to signal and monitor start, duration and intensity of influenza-like illness or ILI (including COVID-19) waves/appearances among NH residents to optimize and support provided health-care, -planning, -management and -policies. In addition, we monitor locally circulating virus types/subtypes or lineages/sub-lineages and their relationship to global and regional patterns.

This study is an prospective observational surveillance with a network of NH that participate voluntarily. This surveillance consists of two components

  • a clinical/epidemiological: in this part of the surveillance, the number of ILI cases and ILI-related hospital admissions and deaths are reported weekly throughout the year.
  • a virological component: when an alarming increase in ILI activity is observed, the virological component is initiated. In this part of the surveillance, nasopharyngeal samples are taken from residents of the NH for virus typing.

Expected outcomes:

  • Incidence of ILI cases, ILI-related hospital admissions and deaths in NH
  • Virus typing of nasopharyngeal samples collected from NH residents (with ILI case): SARS-CoV-2, influenza, RSV-A, RSV-B, hMPV, PIV-1, PIV-2, PIV-3, PIV-4, adenovirus and rhinovirus.

The ILI NH, general practitioner and hospital surveillance data will be reported together, giving a comprehensive view of the ILI incidence in the Belgian population.

For a more detailed overview of this surveillance, consult our protocol


In the figure below an overview is given of the nursing homes that are currently participating in the ILI surveillance.

If you are interested in participating to this surveillance as a nursing home, please contact or

The results are reported in the weekly acute respiratory infections bulletin in French and in Dutch

Sciensano's project investigator(s):

Associated Health Topics

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