The Vicarious Immunity in the context of polio refers to:
- A Immunity transferred via breast milk to neonates
- B Cross-immunity between poliovirus serotypes
- C Immunity acquired by non-vaccinated individuals through contact with OPV-vaccinated contacts who shed vaccine virus ✓
- D Immunity conferred by IPV to mucosal surfaces
Correct answer: C. Immunity acquired by non-vaccinated individuals through contact with OPV-vaccinated contacts who shed vaccine virus
Explanation
Vicarious immunity (contact immunity) is a unique advantage of Oral Poliovirus Vaccine (OPV): vaccinated individuals shed attenuated vaccine virus in feces, which can spread to unvaccinated contacts in the community, immunizing them via the intestinal route. This helps achieve herd immunity even in under-vaccinated communities. IPV does not produce this effect as it does not replicate in the gut or cause fecal shedding.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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