In the context of polio eradication, Vaccine-Associated Paralytic Poliomyelitis (VAPP) is most commonly associated with which OPV serotype?

• A Type 1 OPV
• B Type 2 OPV
• C Equally likely from all three serotypes
• D Type 3 OPV ✓

Explanation

Type 3 OPV is the most common cause of VAPP, followed by Type 2. The risk of reversion to neurovirulence is highest for Type 3 and Type 2 because the attenuating mutations in these serotypes are fewer and less stable. India switched from trivalent OPV (tOPV) to bivalent OPV (bOPV, types 1+3) in 2016, and tOPV was globally withdrawn, partly to eliminate type 2 VAPP since wild poliovirus type 2 had been eradicated.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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