The wheeze of the iron lung, the fear of public places during the summer months, leg braces, deformed limbs—these were once the stark reality of American life without a polio vaccine. Poliovirus epidemics swept through the country during the first half of the 20th century, crippling and killing tens of thousands of people. Then, in 1955, announcement of the success of the first polio vaccine reverberated around the country and the world. Widespread vaccination campaigns and, ultimately, the race to eliminate the disease in the United States began.

Now, more than 50 years later—and with polio a distant memory in this country—two researchers at the Harvard School of Public Health (HSPH) report findings from the first retrospective analysis of the cost-effectiveness of U.S. polio immunization programs. Their discovery is a testament to public health’s mantra: Prevention is better than cure.

In their paper, Kimberly Thompson, an associate professor of risk analysis and decision science in the Department of Health Policy and Management, and Radboud Duintjer Tebbens, a research associate, estimate that the polio vaccination programs, which cost about $35 billion from 1955 to 2005, averted more than 1.1 million cases of the disease and more than 160,000 deaths. The net economic benefits were just as astounding: more than $180 billion saved in treatment costs and deaths avoided. And when the researchers factor in intangibles, such as pain and suffering, the estimated net savings surpass $800 billion.

Credit Where Due
The study, which appeared in December 2006 in a special issue of Risk Analysis devoted to polio, was unique, not just for its retrospective considerations but also because it examined cost savings and net benefits for various U.S. vaccination programs over time. Unlike prior studies, which were only snapshots of single points in time, Thompson and Duintjer Tebbens’s study examines the entire U.S. historical experience, taking into account the dynamic nature of the disease. Their model also assesses the impact on population immunity of the live but weakened oral poliovirus vaccine which, when given to large numbers of people, spreads protection to many who did not receive the vaccine by stimulating their immune systems and creating herd immunity.

“Public health is about prevention,” points out Thompson. “Unfortunately, researchers in the field often do not get credit for the deaths and illnesses that never occur. What makes a study like this so gratifying is that we were able to demonstrate how a vaccine not only saves lives, but also saves large amounts of money.” It is a message she hopes will resonate with health and government officials as the fight against polio continues on a global scale.

The Final Push
At the World Health Organization (WHO), Bruce Aylward, director of the Global Polio Eradication Initiative, echoes Thompson’s views and highlights the importance of her research: “As we stand on the brink of eliminating wild polioviruses around the world, these results provide a glimpse of the massive economic benefits of global polio eradication.” According to WHO, the cost of eradication has exceeded $5 billion to date; another $575 million is needed just to fund efforts for 2007–2008—by no means a paltry sum, but nothing compared to the potential long-term savings, as an April paper by Thompson and Duintjer Tebbens published in the Lancet has shown (see sidebar, right).

In 1988, the year the World Health Assembly resolved to eliminate the poliovirus, polio was endemic in 125 countries, with an estimated 350,000 cases of paralytic polio occurring each year. Today, polio remains endemic in only four countries—Nigeria, Pakistan, Afghanistan, and India—and the total number of reported cases worldwide for the last several years has been less than 2,000. Global polio eradication represents one of the largest and most significant public health efforts under way. “But we cannot celebrate until eradication is achieved,” warns Thompson. “We need to finish polio eradication now.”

Although the number of polio cases may seem small, resurgence is possible. WHO faces considerable hurdles in implementing widespread vaccination programs, including civil unrest and geographical complications. More important, the organization must assuage concerns that immunization efforts aren’t worth the immediate costs—particularly when “out of sight” often means “out of mind” for government officials in developing countries who may be hesitant to earmark scarce resources for what they perceive as a relatively small health threat. Moreover, according to new WHO Director-General Margaret Chan, it has been difficult to debunk rumors about dangers associated with the vaccine.

Thompson and Duintjer Tebbens are now expanding their study beyond the United States to examine the net benefits to date of the global eradication campaign. It’s a daunting task, but one Thompson hopes will give added weight to WHO’s commitment to eliminating polio, despite the hefty price tag. “Taking the long view now,” she says, “could save thousands of lives and billions of dollars, and teach us valuable lessons in the struggle against other widespread infectious diseases.”

To learn more about WHO’s global polio eradication campaign, visit http://www.polioeradication.org. For an account of the work that made the vaccine’s development possible, see

http://www.hsph.harvard.edu/review/review_fall_04/rvw_polio.html

Jesse Nankin is the development communications coordinator for the Office for Resource Development at HSPH.