What is herd immunity?

Herd immunity refers to the concept where a significant portion of a population becomes immune to an infectious disease, which in turn helps to protect individuals who are not immune. This immunity can be achieved through vaccinations or previous infections. When a substantial number of people are immune, the spread of the disease is limited, making it less likely for those who are unvaccinated—such as individuals who cannot be vaccinated for medical reasons or those whose immune systems do not respond to vaccines—to contract the illness.

Achieving herd immunity effectively reduces the overall incidence of disease within the community and can lead to the eventual elimination of the disease if the level of immunity is high enough. This phenomenon highlights the importance of vaccination programs, as community health benefits are derived from protecting not just vaccinated individuals, but the population as a whole.