COVID-19 Case Definitions

This page contains:

• COVID-19 interim case definition for Ireland
• COVID-19 hospital acquired case definition for Ireland
• COVID-19 outbreak case definition for Ireland

COVID-19 interim case definition

Version 5.9

Clinical criteria

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

OR

• Sudden onset of anosmia², ageusia³ and dysgeusia⁴

OR

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 in a clinical specimen

Case classification
Possible:
Any person meeting the clinical criteria

Probable case
Any person meeting the clinical criteria with an epidemiological link
OR
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: <2 metres face-to-face contact for greater than 15 minutes.

Last updated: 25 June 2020

COVID-19 hospital acquired case definition

Version 1.1

Hospital acquired COVID-19 is defined as the following as agreed by EAG and AMRIC oversight group:

• Onset of clinical features of COVID-19 7 days or more after admission should be regarded as hospital acquired COVID-19
• Onset of clinical features of COVID-19 between days 3 and 6 after admission are considered hospital acquired cases of COVID-19 if epidemiologically linked to hospital exposure
• Onset of clinical features of COVID-19 on day 1 or 2 after admission are considered community acquired unless epidemiologically linked to hospital exposure during a recent hospital admission
• If onset of clinical features cannot be defined, a case by case assessment is required taking account of the date of sampling relative to the date of admission, the ct value of the test result and epidemiological evidence of a link to hospital exposure.

Last updated: 18 May 2020

COVID-19 outbreak case definition

Version 3.0

• A cluster/outbreak, with two or more cases of laboratory confirmed COVID-19 infection regardless of symptom status. This includes cases with symptoms and cases who are asymptomatic.
  OR
• A cluster/outbreak, with one laboratory confirmed case of COVID-19, and at least one additional case of illness with symptoms consistent with COVID-19 infection (as per the COVID-19 case definition)

^{* From September 21st 2020, report suspected COVID-19 outbreaks with the disease category ‘Acute Respiratory Infection (ARI)’. If one or more cases linked to the outbreak are subsequently confirmed as COVID-19, the ARI outbreak should be reclassified to being a COVID-19 outbreak. Outbreaks of suspected COVID-19 which were notified before September 21st 2020, and met the previous COVID-19 outbreak definition should remain as COVID-19 outbreaks on CIDR}

Last updated: 21 September 2020