What does herd immunity refer to?

Herd immunity refers to the resistance to disease spread within a population that occurs when a sufficient proportion of individuals are immune to an infectious disease, either through vaccination or previous infections. This immunity creates a protective effect for those who are not immune, as it reduces the overall amount of the pathogen that can spread within the community. When a significant number of people are immune, it limits the opportunities for the disease to spread, thereby protecting vulnerable populations who may not be able to receive vaccinations due to medical reasons.

While immunity developed by individual vaccinations is a part of how herd immunity is achieved, it does not fully describe the concept. The ability of one individual to fight off infections alone does not encompass the communal aspect of herd immunity. Additionally, the proportion of a population that must be vaccinated to prevent disease is related to herd immunity but is a specific detail rather than the broad concept. The key idea of herd immunity is the collective resistance of the population as a whole, allowing for reduced transmission of the disease.