Cobertura imunidade rebanho
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The herd immunity coverage calculator estimates the minimum population percentage required to interrupt disease transmission using the formula 1 − 1/R₀, where R₀ is the basic reproduction number. For example, if R₀ = 3, the threshold is 1 − 1/3 ≈ 66.67%, meaning two-thirds of the population must be immune. It's used for mass vaccination planning and epidemic control.
This tool helps assess whether immunization campaigns have reached the critical threshold to protect vulnerable groups. It works best with accurate R₀ values from epidemiological studies. Common applications include measles, polio, or covid-19, where R₀ varies by strain and social conditions. It doesn't account for factors like immunological variability or vaccine efficacy.
Note: The result is a theoretical estimate. In practice, vaccine effectiveness, real-world coverage, and human behavior may require higher percentages. Combining it with local infection data and vaccination records is crucial for effective public policies.
Frequently asked questions
Why use the 1 − 1/R₀ formula?
This formula is derived from epidemiological theory and represents the minimum collective immunity threshold to interrupt disease transmission.
How does R₀ value affect the calculated coverage?
Higher R₀ requires higher immunity percentages. For instance, R₀=4 demands 75% minimum coverage.
Does the calculator account for vaccine efficacy?
No. It assumes 100% immunity effectiveness. In practice, adjustments should be made using real-world efficacy and vaccination adherence data.
For which diseases is this calculator most suitable?
For highly contagious diseases with known R₀, such as measles, rubella, and covid-19, which benefit from herd immunity.