All of the following are true about herd immunity, EXCEPT:
Herd immunity can be achieved by immunizing a population with a vaccine that interrupts transmission, such as the live, attenuated polio vaccine, but not with a vaccine that does not interrupt transmission, such as the killed polio vaccine (even though it protects the immunized individual against disease). In addition, the live virus in the vaccine can replicate in the immunized person and spread to other members of the population, thereby increasing the number of people protected. Herd immunity can be achieved by natural infection as well as vaccines (e.g., measles). For herd immunity to occur, the vaccine must prevent transmission of the virus as well as prevent disease. Ref: Levinson W. (2012). Chapter 33. Host Defenses. In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.
It can be achieved by immunizing a population with a vaccine that interrupts transmission
The live virus in the vaccine can replicate in the immunized person and spread to other members of the population
Herd immunity can be achieved only by vaccines.
The vaccine must prevent transmission of the virus as well as prevent disease.