dna edit: A virus vanquished

On January 13, when India went three years without a single reported wild polio virus case, the day did not witness much of the chest-thumping that accompanies sporting or scientific feats. It is a stupendous achievement for a country that has borne the ignominy of being an endemic country for wild polio virus cases for long. The credit must go to a mammoth effort involving over two million volunteers who participated in immunisation and surveillance campaigns, state and central governments, UNICEF and WHO, scientists who developed the bivalent oral polio vaccine that was introduced with telling effect in 2010, and the innovative social strategies that endeared community health workers to the masses.

The turnaround has been significant because India, at 741 cases, logged more than half the cases reported worldwide in 2009. From 500 cases daily in 1970s, to 43 cases in 2010, and finally the last reported case in January 2011 from West Bengal, the polio immunisation drive has also helped build a strong cadre of rural grassroots mobilisers for public health programmes.

With India expecting a polio-free certification from the WHO, there are many lessons to be learnt and carried forward to help combat other diseases. From the days when vicious rumours circulated  that the polio vaccine caused impotence and set back the campaign by many years, it has innovated into a broadbased initiative that educates people about sanitation and hygiene, on diarrhoea prevention and ending open defecation, and the importance of immunisation. In most North Indian villages, these community mobilisers are a ubiquitous sight going around households on door-to-door campaigns, filling out data sheets on the immunisation and health status of household members. The tabulation of this data helped prepare a strong surveillance system for poliovirus detection in humans and in the environment.

Though no poliovirus has been detected among humans or in the environment since 2011, India cannot afford to let its guard down yet; two of the remaining three polio-endemic countries — Pakistan and Afghanistan — are nearby. Just as India regularly exported the poliovirus to neighbouring countries in earlier years, the chances of the favour being returned cannot be ruled out. Of the 372 cases reported in 2013, 148 were reported from Pakistan, Afghanistan and Nigeria. What is worrisome is the continuing viral outbreaks in new parts like Syria, Somalia, Ethiopia, Kenya and Cameroon where the remaining 224 cases were reported.

India’s focus must shift to sanitation, improving sewage systems, and encourage boiling of drinking water. In areas where dry latrines and hence open defecation are still in vogue, the conversion to pour-flush toilets must be incentivised. A dampener has been the steady incidence of non-polio acute flaccid paralysis (NPAFP) cases. Experts are yet to prove its link to polio vaccine doses, but an estimated 53,000 cases of this paralytic condition were reported in India in 2013, especially in UP and Bihar. The government and WHO claims that these cases were discovered because of the heightened polio surveillance programmes and are unrelated to polio vaccination.

But independent experts worry if higher doses and repeated rounds of polio vaccination in these states could be responsible for the paralysis. The vigil against polio should continue until the NPAFP condition can be conclusively understood.