India achieved polio-free certification in 2014. The 'Polio Endgame Strategy' required switching from trivalent OPV (tOPV) to bivalent OPV (bOPV) plus IPV. The primary reason for introducing at least one dose of IPV into the schedule was to:

• A Replace bOPV as the only polio vaccine in the schedule
• B Provide intestinal immunity against wild poliovirus type 3
• C Provide mucosal immunity against all three poliovirus serotypes
• D Protect against vaccine-derived poliovirus (VDPV) — especially type 2 — after tOPV withdrawal ✓

Explanation

After the April 2016 global switch from tOPV to bOPV (types 1 and 3 only), the Sabin type 2 component was removed — creating a 'type 2 immunity gap'. IPV (inactivated, containing all 3 serotypes) was introduced to provide systemic immunity against type 2 poliovirus and protect against circulating vaccine-derived poliovirus type 2 (cVDPV2). IPV provides excellent systemic immunity but limited intestinal/mucosal immunity (which is provided by OPV). Under India's NIS, IPV is given at 6 and 14 weeks (fractional IPV intradermally).

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.