OPV cannot eradicate polio from India: do we need any further evidence?

Polio eradication programme was launched in India in 1995, and polio eradication was expected to occur by 2000. Remarkable decline in polio incidence occurred, but, polio was not eradicated. Majority of polio cases are occurring in two states viz., Uttar Pradesh and Bihar. It is also being observed that majority of polio cases had received many doses of polio vaccine. In 2005 monovalent OPV1 (mOPV1) and monovalent OPV3 (mOPV3) were also introduced in Uttar Pradesh and Bihar, but, number of polio cases increased 10-fold in 2006. In 2007 number of vaccination rounds were increased to one round every month, but in 2007 number of polio cases increased further. In 2005 there were 66 polio cases whereas in 2006 and 2007 number of polio cases increased to 676 and 863, respectively. Some genetic factors in children from Uttar Pradesh and Bihar appear to be responsible for poor antibody generation by OPV. Some mutations in polio viruses may be responsible for development of resistance to antibodies generated by OPV and a reason for the recent steep rise in polio incidence since 2006. Because of these two factors, OPV cannot eradicate polio from India.