Modest goals, strategic risks in world polio fight

WASHINGTON -- In both 2000 and 2005, the World Health Organization set deadlines to eradicate polio, the crippling and sometimes fatal virus that caused widespread panic in the United States more than a half-century ago.

Twice it failed to meet the deadlines.

Last week, the organization quietly set more modest deadlines -- aiming to halve this year the numbers of cases in the four countries in which the disease is transmitted, and then reducing those numbers by half again in 2008. That means the numbers of polio cases worldwide could fall to fewer than 500 cases annually by 2008.

But skeptics wonder whether a third failure would doom the ambitious two-decade effort, which has cost $5.3 billion so far and is appealing to donor nations for funds at a time when other diseases such as AIDS and malaria are consuming global health resources.

WHO officials acknowledge they are taking a risk in setting more deadlines, but said they need to show progress in order to secure donor funding. Right now, they need an additional $540 million for the next two years.

"Donors are tired," Bruce Aylward, director of WHO's polio eradication initiative, acknowledged in an interview from Geneva. "And there's always a risk with goals and targets. We have four countries left. If three hit the goal, you are in good shape. If all four of them miss, people will want to take another hard look."

The transmission of polio has been stopped in all countries of the world except for Nigeria, India, Pakistan, and Afghanistan. So far this year, WHO reports 155 cases around the world, compared with 315 at the same time last year. In 2006 , nearly 2,000 polio cases were reported, including more than 1,100 from Nigeria alone.

Margaret Chan , WHO director-general , who was appointed six months ago, has made polio eradication one of her top priorities.

She has decided that the only way to eradicate the virus is to win the support of the leaders of the four countries that haven't stopped transmission. So far, she has communicated with the leaders of India, Afghanistan, and Pakistan, and hopes to soon meet with Nigeria's President-elect Umaru Yar'Adua.

Aylward traveled to Nigeria earlier this month and said he saw greater commitment from leaders in northern regions of the country to fight polio. "They're tackling it more aggressively as a group," he said. "There's more ownership of the program on a state level right now."

But a growing number of health specialists have questioned whether continuing the battle to eradicate polio is a wise one. Some believe that the money could be better spent on other interventions, such as child and maternal health. And some doubt whether the job can be done.

The polio effort has made giant strides. In 1988, there were an estimated 350,000 cases. But immunization specialists have always cautioned that the hardest part would come when the numbers became tiny.

Partly that is because with fewer cases, country leaders often don't perceive it as a major problem and want to spend health funds elsewhere. Technical obstacles also loom. One is that vast areas of poor nations no longer vaccinate most children against polio, meaning that if a person brings the virus into those populations, it could spread easily.

Another issue is that the oral polio vaccine contains a live virus, and in an estimated one in a million first doses to a child, the vaccine itself can transmit the disease; as many as 250 cases a year occur because of the oral polio vaccine, health officials estimate.

The United States and other rich countries use an injectable vaccine, which does not contain a live virus and does not transmit the virus.

The end strategy of eradication, specialists say, would likely include a worldwide stoppage of the oral polio vaccine, followed by a period of monitoring to see if new cases appear. At that point, countries may use the injectable vaccine to contain an outbreak. But researchers wonder if fragile countries could mount a large polio vaccination campaign that uses the injectable vaccine.

"Look what happened in Nigeria in the last year -- the virus spread from there to a dozen countries," said Scott Barrett, professor of international relations at Johns Hopkins School of Advanced International Studies. "It dropped into Botswana, which didn't matter because Botswana had high vaccination rates. But when it gets into Somalia, or other failed or dysfunctional states, then it's a real problem."

Barrett, who has extensively studied polio eradication and delivered a lecture earlier this month on the subject at the Harvard School of Public Health, said that success means "going down to the final inch. Getting close is simply not success. So many things have to go right. That's why I think this whole effort is still a huge gamble."

John Donnelly can be reached at donnelly@globe.com.