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.
It refers to group protection beyond what is aforded by the protection of immunized individuals
It is likely to be more for infections that do not have a sub-clinical phase
It is affected by the presence and distribution of alternative animal hosts
In the case of tetanus it does not protect the individual