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What is Which vaccine gives herd immunity- and explain in detail?
Ans. is 'a' i.e., OPV o The vaccine progeny of OPV is excreted in the faeces and secondary spread occurs to household contacts and susceptible contacts in the community. o Non-immunized persons may therefore, be immunized. o Thus widspread "herd immunity"results, even if only approximately 66% of the community is immunized.