Conditional Herd Immunity
The basic reproduction number, R0, for COVID-19 is estimated to be 2.5. With this level of R0, herd immunity is reached when 60% of the population have been infected or recovered. During the COVID-19 epidemic, governments are encouraging/ordering the population to vary their behavior so that the effective value of R is considerably less than 2.5. This raises the prospect of a population reaching herd immunity with only 20% of the population being infected or recovered. This would be conditional herd immunity as it would be conditional on the population maintaining the lower value of R even after the number of infections starts to drop.
Based on a detailed analysis we present the countries listed in order of the expected time to reach conditional herd immunity.
| Rank | Country | Years to Herd Immunity | Immunity (%) | R values | TII (ppm) | Strategy |
|---|---|---|---|---|---|---|
| 41 | Lebanon | 0.22 | 12.56 | 1.11 | 4480.12 | |
| 42 | Albania | 0.22 | 11.79 | 0.89 | 4605.65 | |
| 43 | Greece | 0.26 | 10.86 | 1.19 | 4948.02 | |
| 44 | Serbia | 0.3 | 11.1 | 1.15 | 4060.85 | |
| 45 | Armenia | 0.3 | 17.31 | 1.23 | 1252.07 | |
| 46 | Iran | 0.33 | 12.49 | 1.02 | 3012.23 | |
| 47 | Jordan | 0.34 | 8.59 | 1.24 | 4841.8 | |
| 48 | Ireland | 0.34 | 14.88 | 0.91 | 1885.05 | |
| 49 | Monaco | 0.34 | 11.74 | 0.71 | 2460.59 | |
| 50 | Germany | 0.35 | 14.21 | 1.03 | 2128.14 |