If the battle to eradicate polio were an action movie, this week would be the part where the good guys have racked up spectacular victories – but look like they may lose anyway.

On the spectacular side, polio may be gone in India. Of the four countries where polio remained entrenched, the giant country was expected to be the last to fall. Yet its most recent case was in January this year, whereas by this time last year, it had had 40 cases.

The intestinal-borne virus hasn’t even been found in sewage in India, says Oliver Rosenbauer, spokesman for the polio programme of the World Health Organization, even though the incidence of the disease usually peaks at this time of year.

The victory, says the WHO, is down to repeated, coordinated vaccination drives spearheaded by local officials in affected areas, and the use of a more efficient vaccine that only targets the strains circulating.


Don’t stop now

Yet as long as polio persists somewhere, India must keep doggedly vaccinating. Experts meeting at the WHO in Geneva this month warned that if eradication fails now, it will be “the most expensive public health failure in history”.

In Nigeria, another of the four, cases jumped fourfold this year from last, to 43. “It’s worrying,” says Rosenbauer, as Nigeria has re-infected three neighbouring, formerly polio-free countries. And the area of north-east Nigeria affected is increasingly hard for vaccination teams to access due to an Islamic militant group called Boko Haram.

Still, outbreaks in polio-free areas can be mopped up quickly. Tajikistan, for example, had 460 cases last year, vaccinated, and had none this year. And unlike 2003, when polio in Nigeria soared after local leaders opposed vaccination, those people are now on-side. Cases are down 95 per cent from 2009, and remain only where local leaders have not taken active responsibility for polio.

Faster, stronger

They are starting to, says Rosenbauer. “Our analysis shows the extent of local leadership correlates with viral persistence.” That was key in Nigeria and India, he says. That, and switching from the old vaccine which contained all three strains of polio virus, to a new single-strain vaccine that induces faster, stronger immunity.

That may crack a third endemic country, Afghanistan, where polio persists in the south near Pakistan. Local violence prevented vaccination and nearly tripled cases this year, to 53. But the new vaccine can be given over one week instead of six, allowing vaccinators and, again, local leaders to negotiate lightning-strike vaccinations during lulls in the hostilities.

The real worry is Pakistan, where polio has spread all over from three strongholds in Karachi, Quetta and the north-west tribal area. Cases stand at 145 people infected so far this year, up from 113 last year. In the first two regions the key again will be local leadership, which may be bolstered with a new national vaccination initiative this year, says Rosenbauer.

The wild north-west of the country will be harder – especially as the WHO’s polio campaign, as ever, is short of cash. A quarter of its $2.2 billion budget for 2011-2012 has not yet been donated.