Polio 'Inches' toward Eradication, May 25, 2007, Harvard Public Health NOW

The eradication of smallpox may be public health's greatest achievement, but future eradication of other diseases such as polio is in doubt because of cost, political instability, and the epidemiology of the diseases themselves, said Scott Barrett, professor of environmental economics and international political economy at Johns Hopkins University, during a lecture at HSPH on May 3.

Scott Barrett

"We've been working on polio for 20 years, and the odds are that it won't succeed,'' said Barrett, a visiting scholar at the Harvard University Center for the Environment, during the talk in Kresge G-3.

At the outset of his lecture, "Eradication: The Economics of the Final Inch,'' Barrett quoted the late Soviet dissident writer Alexander Solzhenitzyn about what is known as "the final inch.''

The term refers to the last bit of work before a project is completed. Solzhenitzyn said: "The rule of the final inch...The work has been almost completed, the goal almost attained...In that moment of fatigue and self-satisfaction, it is especially tempting to leave the work without having attained the apex of quality...In fact, the rule of the 'Final Inch' consists in this: not to shirk this crucial work. Not to postpone it.''

According to Barrett, the rule of the final inch is particularly critical when it comes to eradicating a disease. Polio, he noted, has been controlled, but not eradicated. "Eradication is 100 percent,'' he said.

Getting to eradication requires sufficient funding and the agreement of all nations, he said. But some nations are reluctant to pay. Even if sufficient funds are raised by other nations, giving the required vaccinations in countries torn by war or other strife makes the task problematic. At the same time, he noted, some experts doubt that certain diseases, including polio, will be able to be eradicated because of the nature of the viruses themselves.

Barrett said that it is in rich countries' interests to pay for worldwide vaccination programs, even if the diseases have been controlled in their own countries. This is because eradication would save the rich countries money in the long run as they would no longer have to pay to continue to inoculate their own citizens. "The benefit lasts forever,'' he said. (Indeed, two HSPH researchers recently published an analysis in The Lancet indicating that short-term costs of global eradication would be lower than the long-term financial and human health costs required to control polio forever.

But getting to the "final inch'' - identifying the last polio victim on earth - is a difficult proposition when dealing with countries, such as Somalia, where he said there is no effective government. He noted that the last smallpox victim was identified in that country in 1977, but that was before the country became embroiled in chaos.

Barrett said that approximately $5.3 billion has already been raised worldwide in the effort to eradicate polio, but added that there is currently a budget gap of $575 million. One of the threats to eradication is lack of money, he said.

Even a disease such as guinea worm - which can easily and cheaply be controlled by filtering water - still persists due to political instability and conflict in many countries, observed Barrett. So what hope is there for polio eradication?

Barrett commented to HPH NOW, "Will we ever see the last person on earth to have polio or guinea worm? I don't think we know the answer to that. Success with polio depends on a lot of things coming together simultaneously. Success with guinea worm depends on civil conflict ending in Sudan, but the world so far has failed even to prevent genocide in Sudan's Darfur region. In both cases the finish line is near, but the final inch will decide everything."

—ML