Herd immunity is not useful in -: (A) Diphtheria, (B) Polio, (C) Measles, (D) Tetanus
Answer is D. Herd immunity has been achieved in diphtheria and poliomyelitis Small pox-herd immunity has not played a crucial role in its eradication. Tetanus- herd immunity doesn't protect the individuals ( refer pgno:103 park 23 rd edition)