With India achieving ‘polio-free nation’ status, steps are underway to introduce Injectable Polio Vaccine (IPV) from October to completely eliminate the deadly polio virus. A senior official in the Union Health Ministry said that under the routine immunisation programme the orally-administered vaccine, also called as Oral Polio Vaccine (OPV), would be withdrawn first and a dose of inactivated vaccine (IPV) in the form of an injection will be introduced.
Phase I of the strategy involves a global switch from the trivalent to bivalent vaccine by 2016, as recommended by the World Health Organisation. “The introduction of Inactivated Polio Vaccine (IPV) will be taken across the country from October this year prior to this switch. The aim is to introduce IPV in the entire region by the end of this year followed by the global switch in vaccine in 2016,” the official added.
Currently, trivalent oral polio vaccine (TOPV) contains vaccine for Type 1, Type 2, Type viral strains. The Type 2 polio virus strain has not been seen since 1999. To withdraw the vaccine for this virus, IPV will be introduced six months in advance to mitigate any risk. Though India has not reported any polio case in the last four years, it remains under the threat of the attack of the virus which continues to circulate in both endemic countries such Pakistan, Nigeria and Afghanistan and re-infected countries such as Syria, Kenya, Somalia, Iraq and Ethiopia.
Doctors say that while OPV has given good results, the vaccine carries risk of vaccine-associated paralytic polio (VAPP) and vaccine derived polio virus (VDPV) as side effects. Administering IPV would mean immunity to the wild polio virus as well as VDPV. Experts warn that any delay in introducing the IPV can have detrimental effect on public health. Dr T Jacob John, chairman, Child Health Foundation said, “Though we have successfully combated the menace of polio using oral vaccines containing live viruses, it has to be kept in mind that only the wild polio viruses have been eliminated from India, while the vaccine-derived polioviruses still remain a threat.
“IPV, planned to be introduced in 2015, is inevitable if we have to prevent vaccine-derived cases of polio and achieve total eradication of the disease. Once IPV is launched to preempt circulating vaccine-derived poliovirus, we can gradually discontinue OPV, starting with type 2 component,” said T Jacob John. But for IPV to be effectively deployed, routine immunisation coverage has to be improved. Overall the coverage is around 80 per cent with some of the States like Uttar Pradesh reporting much lower than the national average.