Table 2 Applied definitions in the COVID-19 surveillance in Belgian nursing homes (NHs) [19]

 Since 12 May 2020

Person with laboratory confirmation of SARS-CoV-2 via a molecular test (polymerase chain reaction (PCR) or rapid antigen test), irrespective of clinical signs and symptoms. A symptomatic confirmed case stays a confirmed case until 14 days after the onset of signs/symptoms AND with at least 3 days without fever AND with a significant improvement in respiratory symptoms. An asymptomatic confirmed case stays a confirmed case until 14 days after the positive test. If the resident has a negative laboratory test within this time span, he/she remains a confirmed case.

 Before 12 May 2020

Person with an acute upper or lower respiratory tract infection not present before OR who deteriorated if the patient shows chronic respiratory symptoms.

 Since 12 May 2020

Person

- with at least one of the following main signs/symptoms of an acute viral infection: cough, dyspnoea (shortness of breath), thoracic pain, acute anosmia (loss of the sense of smell) or dysgeusia (distortion of the sense of taste) without obvious cause;

OR

- with at least two of the following signs/symptoms: fever, muscle pain, fatigue, rhinitis, sore throat, headache, anorexia, watery diarrhoea with no obvious cause, acute confusion, sudden fall with no obvious cause;

OR

- with worsening of chronic respiratory symptoms (chronic obstructive pulmonary disease, asthma, chronic cough,…);

OR

- who did not have a laboratory test or whose laboratory test is negative, but who is diagnosed with COVID-19 based on a suggestive clinical presentation and a compatible computed tomography (CT) thorax.