COVID-19 interim case definition

Version 6.1

Clinical criteria

  • A patient with acute respiratory infection (sudden onset of at least one of the following; cough, fever1, shortness of breath)


  • Sudden onset of anosmia2, ageusia3 or dysgeusia4


A patient with severe acute respiratory infection (fever and at least one sign/symptom of respiratory disease (e.g. cough, fever, shortness of breath)) AND requiring hospitalisation (SARI) AND with no other aetiology that fully explains the clinical presentation.

Clinical judgement should be applied in application of these criteria to determine who requires testing.

Epidemiological criteria
At least one of the following two epidemiological links:

  • close contact5 with a confirmed case COVID-19 case in the last 14 days prior to onset of symptoms
  • having been a resident or staff member, in the 14 days prior to onset of symptoms, in a residential institution for vulnerable people, where ongoing COVID-19 transmission has been confirmed

Diagnostic imaging criteria
Radiological evidence showing lesions compatible with COVID-19

Laboratory criteria
Detection of SARS-CoV-2 nucleic acid or antigen in a clinical specimen6

Case classification
Any person meeting the clinical criteria

Probable case
Any person meeting the clinical criteria with an epidemiological link
Any person meeting the diagnostic imaging criteria

Confirmed case
Any person meeting the laboratory criteria

[1] Fever may be subjective or confirmed by healthcare worker (≥380C).

[2] Loss of sense of smell

[3] Loss of sense of taste

[4] Distortion of sense of taste

[5] Close Contact: Any individual who has had face-to-face contact with a COVID-19 case within two metres for more than a total of 15 minutes over a 24-h period (even if not consecutive)

[6] Rapid Antigen Tests should be performed within 5 days of onset of symptoms or within 7 days from time of last exposure to a case. As the sensitivity and specificity of antigen tests depend on the test used, the personnel carrying out the test and the clinical indication or setting in which they are used, at present antigen testing undertaken outside the governance of the public laboratory service is not recognised for the purpose of notification of SARS-CoV-2/COVID-19.

Last updated: 03 August 2021