War on polio hits a wall in volatile Afghanistan

WASHINGTON -- The nearly two-decade, $5 billion campaign to eradicate polio has made significant gains in reducing the virus's strongest strain, but the global battle is in a difficult end game: Fighting in Afghanistan has kept vaccinators from reaching about 100,000 children for nearly a year, allowing the disease to flourish in the remote region.

The overall effort to wipe out the most severe strain of the polio virus has registered a dramatic turnaround in only a matter of months, however. Just 146 cases of that strain have been reported so far this year worldwide, compared with 1,667 in all of last year.

If that trend continues, the global campaign this year will record the fewest number of type 1 polio cases ever, health officials said in interviews.

When the eradication campaign began in 1988, the crippling, sometimes deadly virus was still being transmitted in 125 countries, paralyzing more than 1,000 children a day. Today, only four countries -- Nigeria, India, Pakistan, and Afghanistan -- have significant rates of transmission, and just 2,000 cases were reported worldwide last year.

Still, it was the highest number of reported polio cases in seven years. Some critics have questioned whether public health advocates could reach the goal of complete global eradication of the disease, like the elimination of smallpox.

The recent success, coming after a string of disappointing years during which the disease rebounded, can be traced to changes in strategy made in 2006. The most important decision involved using vaccinations targeted at a specific strain of polio, instead of a vaccine that targets all three strains at once, organizers said.

Type 1 not only paralyzes people at higher rates than the two other types, but also is more easily transmitted and spread. Genetic tests on cases in far-flung regions are almost always found to be type 1 polio.

Organizers also scheduled vaccination campaigns closer together to increase the immunity of children under age 5, especially in densely populated parts of India's Uttar Pradesh and Bihar states, where about 20 million children are immunized in each effort.

"By late last year we were after a shift in the tools and tactics. More of the same wasn't going to get it finished," said Bruce Aylward, director the polio eradication initiative at the World Health Organization.

Overall, 345 polio cases have been reported worldwide of types 1 and 3 this year, compared with 872 at this time in 2006. But the dropoff in type 1 polio cases is even more dramatic.

The state of Kano in northern Nigeria, for instance, had 303 cases of type 1 polio in 2006, but has had no cases this year. In 20 districts in urban western Uttar Pradesh state in India -- considered by veterans of the campaign as perhaps the most stubborn area of polio resistance in the world -- just three cases of type 1 have been reported so far this year.

Last year, all of Uttar Pradesh had 548 type 1 cases.

Still, the eradication campaign faces other stiff challenges, including funding gaps, the rise of one of the other strains of polio, and the lack of access to children in parts of Afghanistan.

The program needs $60 million from global donors by November, and an additional $355 million by the end of next year to continue. It received one major break in June when GAVI (formerly the Global Alliance for Vaccines and Immunization), which supports immunization efforts around the world, contributed an advance of $100 million to support the eradication campaigns; the group had set the money aside to buy large quantities of the vaccine in the event that eradication was achieved.

Transmission of type 3 polio, meanwhile, has shown no signs of abating, with 199 cases so far this year, compared with 331 last year. Organizers said it was due to the focus on combating type 1; several recent rounds of vaccinations aimed at type 3 polio have begun recently in several areas.

The last known case of type 2 occurred in India in 1999.

The problem in Afghanistan seems especially troublesome because there is no immediate fix. The country has recorded seven polio cases so far this year, and while that represents a small number, officials worry the figure could jump quickly.

Dr. Tahir Mir, the WHO team leader on polio eradication in Afghanistan, said by phone from Kabul that bursts of fighting between NATO-Afghan troops and Taliban-Al Qaeda forces have made areas of Helmand Province too dangerous for his teams of vaccinators. The ongoing combat has made the region inaccessible for nearly a year, he said.

"Our campaigns are going down and down because of this almost-war situation in Helmand," he said. "We haven't been able to access all the children. We are totally stuck in the southern region."

While the Afghan government and the NATO-led International Assistance Security Force are willing to commit to a cease-fire during planned vaccine campaigns, Mir said, he cannot strike a similar deal with Taliban and Al Qaeda forces because their leaders are often impossible to reach.

"In some places, there's no visible leadership," Mir said. "Where we can talk with them, it's a mixed response. Some help, some don't."

The result, he said, is that polio will flourish in southern Afghanistan without a negotiated breakthrough. "It looks to be a very happy virus," he said. "Unfortunately, we cannot attack it."

John Donnelly can be reached at donnelly@globe.com