On Jan. 13, India completed two years since its last wild polio case, which was in West Bengal state. The World Health Organization says for a country to be declared polio-free, it must complete three years without a single case of polio caused by the wild polio virus.
The solution is to keep “routine immunization very high,” said Naveen Thacker, a doctor and polio expert. He said there “is nothing to panic” about in the Maharashtra case as there is no outbreak. The baby died from vaccine-derived polio.
If a population is fully immunized, it will be protected against vaccine-derived and wild polio virus, the WHO says.
In the oral polio vaccine, a weak polio virus is used to develop immunity against wild polio. The vaccine replicates in the intestine for a limited period, developing immunity and antibodies. The vaccine-virus during this time is also excreted, passing immunity to the surrounding population before dying out. If, however, the area is seriously under-immunized, the virus can survive longer and in rare occasions undergo genetic changes and become dangerous.
The problem is aggravated by poor hygiene conditions, more typically found in rural areas. Latur, where the baby died, is in southeast Maharashtra on the border with Karnataka.
“The child had developed encephalitis and some other complications and hence we couldn’t save him,” said Shakira Vijay Savaskar, head of pediatrics at the Government Medical College in Latur.
India has been using the oral polio vaccine for 35 years. It had one case of vaccine-derived polio in 2012 and seven cases in 2011, according to the National Polio Surveillance Project. This is the third case in India in 2013.
The disease usually affects children under five.
India is regarded as a success story in the fight against polio eradication. In 2009, 741 cases of polio were reported, more than any other country in the world, and almost half of cases reported globally that year. Yet in 2012, the WHO officially struck India’s name from the list of polio-endemic countries. Only Pakistan, Nigeria and Afghanistan remain on the list.
But as long as polio is present anywhere in the world, chances of the virus resurfacing in India cannot be ruled out. “We have to be vigilant,” said Mr. Thacker.
Source: Wall Street Journal India