Herd immunity is not important in:
The epidemics wave declines with a up-built of herd immunity after natural infection and if high level immunity maintained with immunization disease eliminated, e.g. Polio, Diphtheria. It is neither possible nor necessary to achieve 100% herd immunity. In a population to halt an epidemic or to control disease. E.g. small pox eradication.
In the case of tetanus it does not protect the individual.
Epidemiology of Infectious
Diseases
Tetanus
Pertussis
Diphtheria
All