AP BIOLOGY

Detailed explanation-1: -’Herd immunity’, also known as ‘population immunity’, is the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection.

Detailed explanation-2: -Herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease. The spread of disease from person to person becomes unlikely when herd immunity is achieved. As a result, the whole community becomes protected-not just those who are immune.

Detailed explanation-3: -Herd immunity occurs when the majority of a population is immune to a disease or virus. Otherwise known as community immunity 1, it helps to slow the spread of infectious diseases in two ways : People contract the disease and develop an immune response.

Detailed explanation-4: -The induced herd immunity of a given vaccine exhibits geographic variation as it depends upon coverage and efficacy of the vaccine, both of which can vary geographically. Herd effect is determined by herd immunity as well as the force of transmission of the corresponding infection.