Emergencies preparedness, response

Revised interim case definition – novel coronavirus

This interim case definition is placed here for reference purposes. It has been superseded by a more recent case definition. Please use the link below to access the most recent case definition.

Interim case definition as of 29 September 2012

Case finding and classification scheme for Severe Acute Respiratory Infections associated with novel coronavirus infection:

The following scheme is recommended for identifying cases that should be tested for infection with the novel coronavirus recently described. The goals of this scheme are to ensure a systematic approach to appropriate identification and investigation of patients who may be infected with the virus without overburdening health care systems with unnecessary testing. It should be noted that this information was developed based on data from two confirmed cases and as such some degree of clinical judgment is required where individual cases are concerned.

Patients to be investigated (referred to as “Patient Under Investigation”):

  • A person with an acute respiratory infection, which may include fever (≥ 38°C , 100.4°F) and cough; AND
  • suspicion of pulmonary parenchymal disease (e.g. pneumonia or Acute Respiratory Distress Syndrome (ARDS)) based on clinical or radiological evidence of consolidation; AND
  • travel to or residence in an area where infection with novel coronavirus has recently been reported or where transmission could have occurred;* AND
  • not already explained by any other infection or aetiology, including all clinically indicated tests for community-acquired pneumonia according to local management guidelines.

Management of Patients Under Investigation:

Patients falling into this category should undergo routinely available laboratory tests as clinically indicated according to local management guidelines for Community-Acquired Pneumonia to determine the presence of other potential primary aetiologies of pneumonia. Examples of other aetiologies might include streptococcus pneumoniae, hemophilus influenza type B, legionella pneumophila, other recognized primary bacterial pneumonias, influenza, and respiratory syncytial virus. It is not necessary to wait for all test results for other pathogens to be available before testing for novel coronavirus. In addition, patients with a clear history and clinical presentation consistent with chemical pneumonitis or smoke inhalation should not be considered as a patient under investigation.

If the respiratory disease is unexplained, appropriate clinical specimens should be sent for laboratory investigation. Rapid progress has been made in the characterization of the novel coronavirus, and in the development of sensitive and specific diagnostic assays. WHO is collaborating with partner laboratories to make these available as quickly as possible. It is anticipated that the first batch of reagents, together with information and testing algorithms, will be available for urgent testing within the coming days.

Until then, WHO is able to provide contact information of laboratories willing and able to test for the presence of the novel coronavirus. For further details, national authorities should contact their respective International Health Regulations Contact Point at their WHO Regional Office.

Appropriate infection control measures should be instituted while the patient is under investigation. Should Member States require further guidance on Infection Prevention and Control, please refer to WHO interim guidelines on Infection prevention and control of epidemic- and pandemic-prone acute respiratory diseases in health care (WHO/CDS/EPR/2007.6).

Management of case contacts

Any person who has had close contact** with a probable or confirmed case while the probable or confirmed case was ill should be carefully monitored for the appearance of respiratory symptoms. If symptoms develop with the first 10 days following the contact, the individual should be considered a “Patient Under Investigation” regardless of the severity of illness and investigated accordingly.

If laboratory data, including histopathological examination of fatal cases, cannot be obtained because the patient has died before specimens are taken, clinical specimens cannot otherwise be obtained, or appropriate laboratory testing for other pathogens is not available, then the patient may meet criteria for “Probable Case” as defined below.

Case definitions for reporting

Probable Case

  • A person fitting the definition above of a “Patient Under Investigation” with clinical, radiological, or histopathological evidence of pulmonary parenchyma disease (e.g. pneumonia or ARDS) but no possibility of laboratory confirmation either because the patient or samples are not available or there is no testing available for other respiratory infections, AND
  • close contact** with a laboratory confirmed case, AND
  • not already explained by any other infection or aetiology, including all clinically indicated tests for community-acquired pneumonia according to local management guidelines.

Confirmed Case

A person with laboratory confirmation of infection with the novel coronavirus.


WHO requests that probable and confirmed cases be reported within 24 hours of being classified as such, through the regional focal point for International Health Regulations at the appropriate WHO Regional Office.

* Currently, these areas would include only Qatar and Saudi Arabia (as of 29 September 2012).

** Close contact includes:

  • anyone who provided care for the patient including a health care worker or family member, or had other similarly close physical contact;
  • anyone who stayed at the same place (e.g. lived with, visited) as a probable or confirmed case while the case was symptomatic.