For example, the common Flu is around 1.3, the Coronavirus (COVID-19) based on early data is 1.4 to 3.9, which is likely inflated due to unreported mild cases. The common Measles is 12-18.
| Values of R0 of well-known infectious diseases | ||
| Disease | Transmission | R0 |
| Measles | Airborne | 12–18 |
| Diphtheria | Saliva | 6–7 |
| Smallpox | Airborne droplet | 5–7 |
| Polio | Fecal–oral route | 5–7 |
| Rubella | Airborne droplet | 5–7 |
| Mumps | Airborne droplet | 4–7 |
| Pertussis | Airborne droplet | 5.5 |
| HIV/AIDS | Sexual contact | 2–5 |
| SARS | Airborne droplet | 2–5 |
| COVID-19 (early data) | Airborne droplet | 1.4–3.9 |
| Influenza | Airborne droplet | 1.3–3 |
| Ebola | Body fluids | 1.5–2.5 |
| MERS | Airborne droplet | 0.3–0.8 |
Second, is the deaths per 100,000 people. Because the number of deaths is generally a small, fraction of a percentage, they are measured on a 100,000 scale.
The CDC estimates that so far this season there have been at least 36 million flu illnesses, 370,000 hospitalizations and 22,000 deaths from flu: but possibly as many as 55,000, with a mid point of 38,500. How does this compare to to the COVID-19?