Box 3.

COVID-19 case definition form the US Centers for Disease Control and prevention*

Clinical criteria

In the absence of a more likely diagnosis:

- At least two of the following symptoms: fever (measured or subjective), chills, rigors, myalgia, headache, sore throat, nausea or vomiting, diarrhea, fatigue, congestion or runny nose

OR

- Any one of the following symptoms: cough, shortness of breath, difficulty breathing, new olfactory disorder, new taste disorder

OR

- Severe respiratory illness with at least one of the following: clinical or radiographic evidence of pneumonia, acute respiratory distress syndrome.

Laboratory criteria

Confirmatory laboratory evidence:

- Detection of severe acute respiratory syndrome coronavirus 2 ribonucleic acid (SARS-CoV-2 RNA) in a clinical or autopsy specimen using a molecular amplification test

Presumptive laboratory evidence:

- Detection of SARS-CoV-2 by antigen test in a respiratory specimen

Supportive laboratory evidence:

- Detection of specific antibody in serum, plasma, or whole blood

- Detection of specific antigen by immunocytochemistry in an autopsy specimen

Epidemiologic linkage

One or more of the following exposures in the prior 14 days:

- Close contact with a confirmed or probable case of COVID-19 disease;

- Member of a risk cohort as defined by public health authorities during an outbreak.

Case classification

Suspect

- Meets supportive laboratory evidence with no prior history of being a confirmed or probable case.

Probable

- Meets clinical criteria AND epidemiologic linkage with no confirmatory laboratory testing performed for SARS-CoV-2.

- Meets presumptive laboratory evidence.

- Meets vital records criteria with no confirmatory laboratory evidence for SARS-CoV-2.

Confirmed

- Meets confirmatory laboratory evidence.

*2020 Interim case definition, approved August 5, 2020