As the State goes into yet another round of Pulse Polio Immunisation (PPI) drive on Sunday with oral polio vaccine (OPV), the focus this year will be on intensifying routine immunisation (RI) activities in preparation for the introduction of the injectable polio vaccine (IPV) later in the year, as proposed by the Union Health Ministry.
Since last year, when India was certified polio-free, there has been focus on strengthening routine immunisation activities in all States. In Kerala, the percentage of fully immunised children is just 83 per cent, which needs to be improved before IPV can be introduced.
India’s plans
However, the Centre plans to introduce IPV only to supplement OPV coverage and not make an exclusive shift to IPV, Health officials said. Oral polio vaccine, which uses a live but weak strain of polio virus to provide immunity, has also been found to be responsible for many fresh polio outbreaks across the world, which were caused by vaccine-derived polio viruses, mostly of the type 2 strain.
As part of a global plan for polio eradication, it was suggested that all nations using OPV shift from the current trivalent OPV (effective against type 1, 2, 3 viruses) to a bivalent OPV (against type 1 and 3). However, this shift has to be preceded by the introduction of at least one dose of inactivated IPV, so that any residual threat of type 2 polio virus can be eliminated.
“Many private hospitals in the State have already shifted to IPV totally as part of immunisation. But several studies have proved that in addition to IPV, an extra dose of OPV is necessary to ensure that the children develop gut immunity, which is very crucial for preventing the transmission of virus in the community, especially in areas where sanitation may not be proper,” a Health official said,
Thus, even if a child has been fully immunised against polio using IPV, it makes sense to give him an additional dose of OPV during the current PPI round.
If the introduction of IPV in RI goes as scheduled, trivalent OPV will be administered to infants at six weeks and 10 weeks, followed by an IPV dose at 14 weeks. Another OPV dose follows at 18 months. The shift to bivalent OPV has been planned for 2016.
PPI rounds have been planned for 2016 also. Despite the fact that Kerala reported its last case of polio in 2000, the presence of a large migrant population from polio-endemic States and increased international travel should heighten the risk perception in the State.
Pulse Polio drive in country today
Oral vaccine responsible for fresh outbreaks
