Acute Respiratory Infection

General Information

Acute respiratory infection refers to infection caused by respiratory viruses including SARS-CoV-2, influenza, RSV and other respiratory viruses eg human metapneumovirus.

The respiratory virus season in the Northern Hemisphere runs from October (Week 40) of one calendar year to May (Week 20) of the next calendar year (for instance from week 40 2023 to week 20 2024). Based on historical surveillance data, we know that respiratory viruses are most likely to circulate at detectable levels during this time period however, in Ireland we monitor respiratory viruses all year round.


Acute Respiratory Infection case definition*

*Please note this case definition is for surveillance and management and pertains to RCF settings for the Winter/Spring 2023/2024. This case definition aligns with the European Commission/ European Centre for Disease

  • Sudden onset of symptoms
    At least one of the following four respiratory symptoms:
  • Cough, sore throat, shortness of breath, coryza
  • A clinician’s judgement that the illness is due to an infection

Other relevant case definitions

Acute respiratory infection guidance


Other respiratory virus guidance

 Last updated: 19 January 2024