Respiratory syncytial virus (RSV)

RSV, the “respiratory syncytial virus”, is the virus at the origin of a very common respiratory infection in infants; however, it can occur at any age.

What is an RSV infection?

RSV is a virus which infects the upper respiratory tract (nose and throat).

The symptoms appear 2 to 8 days after exposure and initially resemble those of a cold:

  • blocked or runny nose
  • dry cough
  • moderate temperature.

After the first infection, reinfections are possible throughout life. In adults these are usually just common infections of the upper respiratory tract.

In half of the cases the infection can worsen and reach the lower respiratory tract.

A respiratory infection common in infants

A RSV infection is the most frequent cause of respiratory infection in infants and young children.

Most children suffer their first RSV infection during their first year.

Almost all children have been infected once before the age of 2 years.

A seasonal epidemic

In Belgium and generally in the Northern hemisphere, there is an outbreak of RSV infection in the form of a seasonal epidemic between the beginning of October and the end of March with winter peaks in mid-December.

A very contagious illness

RSV enters the body through the mucous membranes of the nose, eyes and the mouth from the air when there is coughing, sneezing or nose blowing in one’s vicinity, by direct contact with an infected person or by indirect contact through contaminated surfaces or items.

An infection which can become serious

In infants of less than 2 months, the elderly, persons have cardiovascular, pulmonary problems or who have a weakened immune system, an RSV infection can be more serious and develop into pneumonia.

In children an acute middle-ear infection or a bronchiolitis (infection of the smallest airways) can also occur.

Sciensano centralises and analyses all data provided by the different partners (network of sentinel laboratories and the National Reference Centre) and in this way is able to follow up the evolution of RSV infections.

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