India gets WHO boost to use injectable polio vaccine

Study carried out on 1,000 UP children supports govt plan

India gets WHO boost to use injectable polio vaccine

The government’s plan to introduce an injectable polio vaccine in India has received a shot in the arm.

The World Health Organisation (WHO) has come out with scientific evidence confirming the benefits of inactivated polio vaccine (IPV) from a study carried out on close to 1,000 children in Moradabad in Uttar Pradesh.

By firmly establishing the benefits of the IPV, which is given as an injection, the study provides more confidence to the health ministry officials, who have already decided to go ahead with the IPV from October, 2015 in a phased manner, on the advice of the global health body.

“It is the result of this trial, which helped form the polio end-game strategy. It revolutionised our understanding of IPV and how to use it in the global eradication effort,” Bruce Aylward, assistant director general in charge of polio at the WHO and the lead author of the study told Deccan Herald.

Even though the study has been published in the August 21 issue of “Science”, the field work was carried out in 2011 and some of the outcome was known to the researchers.
As per the WHO plan, phasing out of oral polio vaccine (OPV) will begin in 2016 and may be completely phased out from India by 2018-19.

IPV, Aylward said, would be introduced as a single dose to children of 14 weeks from 2015. The main supplier in the next couple of years would be two companies – Sanofi Pasteur and Bilthoven Biological.

Since the development of polio vaccine in the 1950s, efforts to eradicate the polio virus that causes life long paralysis, were mostly restricted to the OPV because it is cheaper and easy to administer.

Another key reason on the vaccine choice was less understanding on the IPV’s role in maintaining a type of immunity inside the body called mucosal immunity.

Mucosal immunity is the protection offered by the linings that separate the sterile interior from the outside world. As OPV diminishes the mucosal immunity several doses are required for protection, which is difficult in conflict zones like Pakistan and Afghanistan – two of the three hotspots in the world where wild polio virus is still in circulation.

That’s why in parts of the world where the polio was difficult to eradicate for a variety of reasons, the choice of vaccine – Salk IPV versus Sabin OPV– always remained a controversial one.

Aiming to remove OPV from the national programme in future, scientists from the WHO and several Indian vaccine manufacturing companies undertook the study. Nearly 1,000 infants and children were given one of the two vaccines. After four weeks, all of them were given a single dose of OPV.

Those who were given the IPV shed less polio virus (from the oral vaccine) in their stool, which meant they were less infective. The IPV group also has better mucosal immunity.

“IPV could play a significant role in curbing the risk of international spread, while efforts to eradicate the disease in the endemic Ares continues to be intensified,” Aylward said.

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