All of the following are true about the Herd immunity for infectious diseases except -

Ans. is 'b' i.e., It is likely to be more for infections that donot have a sub-clinical phase o Herd immunity is more for infections that have a subclinical phase, because by subclinical infection the individual develops immunity against that paicular infection and buildup herd immunity. o Herd immunity implies group protection beyond that afforded by the protection of immunized individuals. Significance of herd immunity Herd immunity predicts occurance of epidemics. o If herd immunity is sufficiently high the occurance of epidemics is highly unlikely. o Herd immunity may lead to elimination of the diseae : - i) Diphtheria and poliomyelitis may be eliminated by stepping up herd immunity. ii) Small pox was eliminated by elimination of source of infection and not by herd immunity.