Herd immunity

![Charlotte Cleverley-Bisman, who had all four limbs partially amputated at the age of seven months due to meningococcal disease. Mass vaccination can prevent children who are too young to be vaccinated from catching transmissible diseases.[13]](/uploads/202501/05/Charlotte_Cleverley-Bisman3303.jpg)


Herd immunity (also called herd effect, community immunity, population immunity, or social immunity) is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection, thereby providing a measure of protection for individuals who are not immune. In a population in which a large number of individuals are immune, chains of infection are likely to be disrupted, which stops or slows the spread of disease. The greater the proportion of individuals in a community who are immune, the smaller the probability that those who are not immune will come into contact with an infectious individual.