Herd immunity plays an important role in all the following disease EXCEPT

(C) Tetanus # Herd immunity: It is the level of the resistance of a community or a group of people to a particular disease.> If that high level of immunity is maintained and stepped up, by an on-going immunization programme, to the point where the susceptible persons are reduced to a small proportion of the population, it may lead (but not necessarily) to elimination of the disease in due course. This has been achieved in such diseases as diphtheria and poliomyelitis.> In the case of smallpox, however, it may be mentioned that it was not herd immunity (although important as it was) that played a crucial role in its eradication, but elimination of the source of infection, by surveillance and containment measures.> With the abolition of vaccination against smallpox, the herd immunity in the case of smallpox will naturally tend to decline with the passage of time. In the case of tetanus, however, herd immunity does not protect the individual.> It is the level of resistance of a community or groups of people to a particular disease.> Elements that contribute to herd immunity are: Occurrence of clinical and sub clinical infection in herd. Herd structure.> Herd immunity has been achieved in case of:- Polio Measles. Diphtheria