Table 1.
Characteristics of SARS-CoV-2, SARS-CoV, and pandemic influenza
| SARS-CoV-2 | SARS-CoV | Pandemic influenza 1918 | Pandemic influenza 2009 | Interpretation | |
|---|---|---|---|---|---|
| Transmissibility, R0 | 2·5 | 2·4 | 2·0 | 1·7 | SARS-CoV-2 has the highest average R0 |
| Incubation period, days | 4–12 | 2–7 | Unknown | 2 | Longer incubation period; SARS-CoV epidemics form slower |
| Interval between symptom onset and maximum infectivity, days | 0 | 5–7 | 2 | 2 | SARS-CoV-2 is harder to contain than SARS-CoV |
| Proportion with mild illness | High | Low | High | High | Facilitates undetected transmission |
| Proportion of patients requiring hospitalisation | Few (20%) | Most (>70%) | Few | Few | Concern about capacity in the health sector |
| Proportion of patients requiring intensive care | 1/16 000 | Most (40%) | Unknown | 1/104 000 | Concern about capacity in the health sector |
| Proportion of deaths in people younger than 65 years out of all deaths | 0·6–2·8% | Unknown | 95% | 80% | SARS-CoV-2 might cause as many deaths as the 1918 influenza pandemic, but fewer years of life lost and disability-adjusted life-years, as deaths are in the older population with underlying health conditions |
| Risk factors for severe illness | Age, comorbidity | Age, comorbidity | Age (<60 years) | Age (<60 years) | .. |
Data from the following references.2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36 MERS-CoV=Middle East respiratory syndrome coronavirus. SARS-CoV=severe acute respiratory syndrome coronavirus. SARS-CoV-2=severe acute respiratory syndrome coronavirus 2.