High-risk groups

In most cases influenza is a benign illness but for elderly people, pregnant women and people with chronic diseases, the complications of flu can be dangerous. Vaccination remains the best way of preventing the complications of flu and hospitalisation.

Who is influenza dangerous for?

Influenza is generally a benign illness but it can be fatal for certain people at risk.

Severe complications (dehydration, infections of the respiratory tract, worsening of chronic illnesses) can occur in people whose immune system is weaker:

  • persons aged 65 and over
  • pregnant women 
  • persons with chronic diseases (respiratory diseases, heart disease, asthma or diabetes)
  • children with chronic diseases or on long-term aspirin therapy.

The mortality risks concern mainly the elderly and patients with chronic illnesses.

Population affected in the case of a new virus

The influenza virus undergoes frequent genetic changes. A population in contact with a new virus will be more likely to be infected.

At-risk groups are more vulnerable to normal seasonal viruses. But if the virus is new to a population, other groups may be affected, particularly younger people.

DID YOU KNOWChildren of over 2 years are not a population at risk. But influenza cases spread much more quickly in children because of the lack of hygiene and the great number of contacts that they have with each other. They are the first to be affected by an epidemic of seasonal influenza, followed by adults some weeks later.

Sciensano coordinates a network of general practitioners and hospitals to ensure the permanent surveillance of influenza activity, of the intensity and severity of epidemics and the impact on the population. Sciensano is also the National Reference Centre (NRC) for influenza virus. The Belgian Official Medicines Control Laboratory (OMCL) of Sciensano, together with the European OMCL network, is responsible for the quality control of the influenza vaccine prior to marketing.

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