A child gets polio drops

New Delhi, Sept. 25: Tens of thousands of children across India were paralysed by polio during the 1980s because health policy makers refused to acknowledge the low efficacy of the oral polio vaccine (OPV) in India, a leading polio expert said.

The low efficacy, which leaves some children unprotected even after multiple doses of OPV, has haunted India’s protracted war on polio and is also evident in western Uttar Pradesh this year where many vaccinated children have developed polio.

“In western UP, the speed of immunisation has not overtaken the speed of the wild polio virus,” said T. Jacob John, former head of virology at the Christian Medical College, Vellore, who is a member of India’s expert group on polio eradication.

Health ministry and polio surveillance officials have attributed the outbreak in Uttar Pradesh this year to the failure of health workers to immunise many children in the region during the second half of 2005.

But they agreed that “rapid and repetitive vaccination with OPV is needed to fight the force of transmission of the wild polio virus”, which is also aided by factors such as high birth rate and poor sanitation.

The low efficacy feature surfaced over 20 years ago when studies in India showed that three doses recommended by the World Health Organisation were not enough to protect all vaccinated children, John said. The proportion of polio cases among children who had received three doses rose steadily through the 1980s.

“Japan wiped out polio with two OPV doses, the US did it with three doses, and India’s southern states used six to eight doses. But in western UP, some children with over 10 doses have still got polio,” John said.

The geographic variation in OPV efficacy is observed even when the quality and potency of the vaccine is excellent.

Following those studies, the Indian Academy of Pediatrics had recommended five doses of OPV. “Five doses would not have eradicated polio, but they would have protected more children than three doses,” a senior pediatrician in a government medical college told The Telegraph.

Yet, the government continued with three doses until 1995. John has estimated that this would have resulted in polio paralysis in tens of thousands of vaccinated children whose parents and doctors had been told that three doses were sufficient. The number could even be as high as 300,000.