Only three endemic countries remain—Pakistan, Afghanistan and Nigeria. But they pose special problems.


Earlier this year, the World Health Organization (WHO) removed India from the list of polio-endemic countries, a victory that involved 2.4 million volunteers administering vaccines to nearly 172 million children. Only three endemic countries remain—Pakistan, Afghanistan and Nigeria—and the 24-year global effort to eradicate the disease is now within striking distance of its goal. But the entire campaign could come undone if obstacles to vaccination stall further progress.

One challenge is geopolitical. In each of the three remaining polio-endemic countries, the disease is concentrated in regions with large Muslim populations that are home to militant insurgencies. There have been persistent rumors in these regions that the vaccine is actually intended to sterilize Muslims, leading to widespread vaccination refusals. Last week, during a national polio vaccination drive under way in Pakistan, violent attacks against health workers took one life and injured two others.

India has set up checkpoints at train stations near its border with Pakistan to vaccinate children as they enter the country. When an outbreak of polio occurred in western China last year, the WHO traced it back to Pakistan; Chinese authorities rapidly mobilized an immunization drive in the area to contain the problem.

But the biggest challenge faced by the polio campaign is a funding shortfall of $945 million—almost half the amount originally budgeted for 2012-13. As a result, many countries, especially in central and western Africa, have canceled or postponed polio immunization drives. This leaves millions of young children at risk from infected individuals who may travel from endemic countries. Since only 1% of the infected develop symptoms, these silent carriers pose a real danger. High vaccination rates in these countries are a must to prevent a resurgence of the disease.

The Global Polio Eradication Initiative's total budget for 2012-13 is $2.19 billion. To date, the initiative has received $1.24 billion in commitments, of which 20% comes directly from the countries conducting the immunization campaigns. Another 15% comes from private institutions including Rotary International and the Bill & Melinda Gates Foundation, 14% from G-8 countries, and 6% from multilateral organizations such as Unicef.

Last month, the Independent Review Board of the Global Polio Eradication Initiative (which serves as an official watchdog over the campaign) warned that cutbacks in vaccination campaigns are "escalating the risk of an explosive return of polio just as it is at its lowest level in history."

The board's report identified 20 African countries that were infected by polio imported from Nigeria from 2006 to 2010—18 of which have now canceled or trimmed vaccination campaigns because of the funding shortfall. It estimated that because of the cutbacks, 94 million children who were supposed to be immunized by the end of the year will not be.

Beyond the urgent and immediate need for full funding, another crucial ingredient for achieving success against polio in the three remaining endemic countries is the strong engagement of political leaders at the national and provincial levels. This has to include a sustained outreach to Muslim religious leaders to win their support in encouraging vaccination among their followers.

Notwithstanding the polio campaign's current challenges, its accomplishments to date have been remarkable. World-wide, there were approximately 650 cases of paralytic polio last year, down from 350,000 each year in the 1980s. A study published in the journal Vaccine in 2010 projected the net economic benefits of the polio-eradication campaign, if taken to a successful conclusion, at $40 billion-$50 billion through 2035.

Vaccines are among the most powerful and cost-effective weapons against disease ever invented by humankind. For example, it takes just a few drops of the orally administered polio vaccine, given in several doses, to protect a child from polio for a lifetime—at a cost of only $0.11 to $0.14 per dose.

A Global Vaccine Action Plan was recently completed through a massive collaborative effort assisted by the Boston Consulting Group. Developed by 1,100 experts from almost 300 organizations, it provides a blueprint for achieving the eradication of polio and control of other diseases such as measles and rubella. With sufficient funding and political will, victory is within reach.

Mr. Winsten is an associate dean at the Harvard School of Public Health. Ms. Serazin is a principal in the Washington, D.C., office of the Boston Consulting Group

As reported in the Wall Street Journal