Paper II — 2024 March (Supplementary) (2019 Scheme) — Q9
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Paper II
2024 March (Supplementary) (2019 Scheme) · 100 marks · 180 min
Question
Polio vaccines and current vaccination schedule for polio
Q94 marksShort Answers
Answer
Polio vaccines:
Oral Polio Vaccine (OPV) — a live attenuated (Sabin) trivalent/bivalent vaccine, given orally; induces strong mucosal (intestinal) immunity, interrupting faeco-oral transmission, making it central to global eradication efforts given its ease of administration and low cost; carries a small risk of Vaccine-Associated Paralytic Poliomyelitis (VAPP) and can, in areas of low immunization coverage, give rise to circulating Vaccine-Derived Poliovirus (cVDPV).
Inactivated Polio Vaccine (IPV) — a killed (Salk) vaccine, given by intramuscular/subcutaneous injection; induces strong humoral (systemic) immunity without the risk of VAPP, but weaker mucosal immunity than OPV.
Current vaccination schedule (India, Universal Immunization Programme): a combination schedule using both vaccines — OPV doses given at birth (0), 6, 10, and 14 weeks, with booster doses at 16–24 months and 5 years; at least one dose of IPV (given intramuscularly, typically alongside the 6- and 14-week OPV doses, per the fractional/full-dose IPV schedule adopted as part of the global polio endgame strategy) is incorporated into the routine schedule to boost humoral immunity and provide protection against Type 2 poliovirus (following the global switch from trivalent to bivalent OPV, given the eradication of wild poliovirus type 2). Additional Pulse Polio (National Immunization Days) rounds with OPV are conducted periodically as part of India’s polio eradication surveillance and response strategy.
