India was certified polio-free in 2014. The Global Polio Eradication Initiative currently uses bivalent oral polio vaccine (bOPV) and not trivalent OPV. The reason type 2 component was withdrawn from routine OPV is:
- A Type 2 component caused excessive intussusception in infants
- B Type 2 OPV had poor immunogenicity compared with IPV
- C Type 2 was replaced by an inactivated component in pentavalent vaccine
- D Type 2 wild poliovirus was eradicated globally in 1999, and continued type 2 OPV use caused circulating vaccine-derived poliovirus type 2 (cVDPV2) ✓
Explanation
Wild poliovirus type 2 (WPV2) was declared eradicated globally in September 1999. Continued use of the type 2 component in tOPV led to circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreaks in under-immunized populations, because the attenuated type 2 strain can revert to neurovirulence and spread. Therefore, in April 2016 (Switch Day), tOPV was globally replaced by bOPV (types 1 and 3), with IPV added to national schedules to maintain type 2 immunity. India introduced IPV as the 2nd dose of penta-IPV combination. Intussusception was a concern with the first-generation rotavirus vaccine, not OPV.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
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Written and medically reviewed by the StethoPrep medical team.