Table.
Case definition of COVID-19 outside Hubei province
| Version 1 (Jan 16, 2020) | Version 2 (Jan 22, 2020) | Version 3 (Jan 23, 2020) | Version 4 (Jan 27, 2020) | Version 5*(Feb 4, 2020) | Version 6 (Feb 19, 2020) and 7 (Mar 4, 2020) | |
|---|---|---|---|---|---|---|
| Clinical criteria | ||||||
| 1 | Fever | Fever | Fever | Fever | Fever or symptoms of respiratory infections, or both | Fever or symptoms of respiratory infections, or both |
| 2 | Radiographic evidence of pneumonia-like patterns, such as areas of consolidation and ground-glass opacity with bilateral peripheral involvement | Radiographic evidence of pneumonia-like patterns, such as areas of consolidation and ground-glass opacity with bilateral peripheral involvement | Radiographic evidence of pneumonia-like patterns, such as areas of consolidation and ground-glass opacity with bilateral peripheral involvement | Radiographic evidence of pneumonia-like patterns, such as areas of consolidation and ground-glass opacity with bilateral peripheral involvement | Radiographic evidence of pneumonia-like patterns, such as areas of consolidation and ground-glass opacity with bilateral peripheral involvement | Radiographic evidence of pneumonia-like patterns, such as areas of consolidation and ground-glass opacity with bilateral peripheral involvement |
| 3 | Low or normal white blood cell count, or low lymphocyte count | Low or normal white blood cell count, or low lymphocyte count | Low or normal white blood cell count, or low lymphocyte count | Low or normal white blood cell count, or low lymphocyte count | Low or normal white blood cell count, or low lymphocyte count | Low or normal white blood cell count, or low lymphocyte count |
| 4 | Antibiotic treatment for 3 days without improvement | .. | .. | .. | .. | .. |
| Epidemiological criteria | ||||||
| 1 | Living in Wuhan or travel history to Wuhan, or direct or indirect exposure to a wet market in Wuhan within 14 days before symptom onset | Living in Wuhan or travel history to Wuhan within 14 days before symptom onset | Living in Wuhan or travel history to Wuhan within 14 days before symptom onset | Living in affected regions (ie, Wuhan or regions with sustained local transmission) or travel history to affected regions within 14 days before symptom onset | Living in affected regions (ie, with any confirmed case) or travel history to affected regions within 14 days before symptom onset | Living in affected regions (ie, with any confirmed case) or travel history to affected regions within 14 days before symptom onset |
| 2 | .. | .. | .. | A link to any confirmed infections | A link to any confirmed infections (ie, positive result from testing of viral RNA) | A link to any confirmed infections (ie, positive result from testing of viral RNA) |
| 3 | .. | Contact with patients with fever and symptoms of respiratory infection from Wuhan within 14 days before symptom onset | Contact with patients with fever and symptoms of respiratory infection from Wuhan within 14 days before symptom onset | Contact with patients with fever and symptoms of respiratory infection from affected regions within 14 days before symptom onset | Contact with patients with fever and symptoms of respiratory infection from affected regions within 14 days before symptom onset | Contact with patients with fever and symptoms of respiratory infection from affected regions within 14 days before symptom onset |
| 4 | .. | .. | Link to any clusters of suspected cases | Link to any clusters of suspected cases | Link to any clusters of suspected cases | Link to any clusters of suspected cases |
| Case confirmation criteria | ||||||
| 1 | Respiratory sample positive by whole-genome sequencing | Respiratory sample positive by sequencing | Respiratory sample positive by sequencing | Respiratory or blood sample positive by sequencing | Respiratory or blood sample positive by sequencing | Respiratory or blood sample positive by sequencing |
| 2 | .. | Respiratory sample positive by RT-PCR | Respiratory sample positive by RT-PCR | Respiratory or blood sample positive by RT-PCR | Respiratory or blood sample positive by RT-PCR | Respiratory or blood sample positive by RT-PCR |
Using the National Health Commission definition, a suspected case was defined as a case that meets three clinical criteria, or two clinical criteria and one epidemiological criterion. A confirmed case was defined as a suspected case that meets one or more case confirmation criteria. COVID-19=coronavirus disease 2019.
In version 5 of the case definition, a confirmed case was defined as a suspected case that met one or more case confirmation criteria; however, between Feb 4 and Feb 18, when version 5 was adopted, a separate category, called clinically confirmed case, applied to cases in Hubei only—ie, defined as a suspected case with radiographic evidence of pneumonia-like pattern, such as areas of consolidation and ground-glass opacity with bilateral peripheral involvement. This separate category led to a sharp increase in the number of confirmed cases in Hubei; however, this change in case definition did not affect our analysis of confirmed cases in cities and provinces outside Hubei.