The last mile

The world witnessed only 223 polio cases last year, the lowest level in history and an impressive advance from the hundreds of thousands of children afflicted as recently as the 1980s. However, the eradication quest is not over, and the next steps look difficult. The Global Polio Eradication Initiative, an umbrella group, has unveiled a promising strategy over the next five years to reach zero cases, the elusive goal first set a quarter-century ago.

The polio virus is highly contagious, can spread rapidly and remains endemic in Pakistan, Afghanistan and Nigeria. In Pakistan, 15 health workers in the anti-polio campaign have been killed since July, and a World Health Organization official estimated that 240,000 children have missed vaccinations in the tribal areas because of security concerns.

Wiping out a disease is an extraordinary accomplishment; it has been done only once before, with smallpox. Yet as polio case numbers plunge, the task of complete eradication grows harder. The oral polio vaccine, which contains a live, weakened virus, has been key to the dramatic progress in reducing cases. But on very rare occasions, the virus strain in the oral vaccine has reverted to a paralytic one and begun to circulate. The new global strategy involves a switch to an inactivated vaccine that can attack the circulating virus. This requires a shot, not just an oral drop.

The five-year strategy is estimated to cost $5.5 billion from varied sources, according to the eradication initiative, a partnership spearheaded by the WHO, Rotary International, the Centers for Disease Control and Prevention and UNICEF with support from the Bill & Melinda Gates Foundation.

Hopes for wiping out polio globally have been raised by the achievement of India, now free of the virus. But success is not assured and demands a fight to the finish.