How vaccines helped India defeat polio while Pakistan became a reservoir for the virus

The diverging fortunes of India and Pakistan in recent years show what an effective vaccination push can do to tackle disease. In 2002 India suffered 1,599 cases of polio, 17 times more than Pakistan experienced that year, according to the World Health Organization. Yet a little more than one decade later India has eradicated polio, while a city in Pakistan is being called the world's "largest reservoir" of the virus.

India was once viewed as the biggest challenge in the campaign to eradicate polio, with its densely populated cities, poor sanitation and weak healthcare system aiding the virus and undermining vaccination teams. Through a combination of government commitment, close collaboration with international partners and the introduction of a bivalent polio vaccine, India overcame these problems. Last week marked three years since the last case of polio in India.

Over the decade that India brought polio under control, its neighbor Pakistan's eradication effort floundered. Resistance from pockets of the Muslim community--which India also faced--and other factors have hindered the campaign to control the disease. This week, the World Health Organization (WHO) showed just how bad things are in Pakistan when it described Peshawar, a city in the northwest of the country, as the "largest reservoir" of polio in the world.

WHO made the claim after analyzing the genetics of the viruses causing current polio cases. Of the 91 cases of polio in Pakistan last year, 83 were genetically linked to strains circulating in Peshawar. The Peshawar strains were also linked to 12 of the 13 cases in Afghanistan last year. And over the past 6 months every sample taken from sewage in Peshawar has tested positive for a highly contagious wild polio virus strain, AFP reports.

Peshawar has become a polio hot spot for two reasons. Firstly, it is a transit hub and the virus arrives and leaves with the many visitors to the city. More importantly, efforts to eradicate the virus are being hindered by the security situation. Militants have attacked vaccination teams and WHO now views some areas of Peshawar as too dangerous for health workers to visit. "The prevailing security situation in Peshawar is resulting in inadequate coverage of children against the virus," WHO said.

- read the AFP report
- here's the BBC's India coverage