The near-eradication of polio is one of the most remarkable public health achievements in the history of the world. Yet, ironically, 50 years after an effective polio vaccine was first introduced, public health officials are now faced with re-fighting a battle they thought they’d already won.
The poliomyelitis virus is extremely infectious, spread through fecal-oral or oral-oral transmission, replicating in the pharynx and gastrointestinal tract, then crossing into the central nervous system where it can destroy motor neurons and, in 1% of cases, leave its victims paralyzed. In the first part of the 20th Century, polio was responsible for a series of terrifying epidemics in the United States, including one that lasted from 1943 to 1956, in which 400,000 people were infected and 22,000 died.
People 50 and older remember polio. They remember friends and classmates who were stricken with the disease, healthy kids who died suddenly or were left paralyzed or crippled. They remember being forced to stay inside during the summer months, warned against swimming pools and large crowds. And they remember the treacherous iron lung machines that kept children breathing through artificial ventilation.
America remained in the grips of this disease until Jonas Salk, M.D., introduced the inactivated polio vaccine in 1955. Six years later, Albert Sabin, M.D., developed a live oral vaccine, clearing the way for mass inoculations. In communities across the country hordes of people headed to local churches, gymnasiums or meeting halls, forming lines that wrapped around city blocks, for the chance to swallow a sugar cube with a dollop of pink vaccine on top.
With dramatic speed, polio began to disappear. In 1960, 2,525 cases of paralytic polio were reported in the United States. By 1965, there were only 61. The last case of wild-virus polio in this country was in 1979, when the disease was imported from the Netherlands and members of Amish communities in several states were infected.
As polio began to fade away in the United States, the World Health Organization (WHO) and other groups turned their attention to other nations. According to the CDC, a polio eradication program conducted by the Pan American Health Organization succeeded in essentially wiping out the disease from the Western Hemisphere as of 1991. Polio is now endemic in only six countries—India, Pakistan, Nigeria, Afghanistan, Niger and Egypt—with 667 paralytic cases in 2003, 300 of which occurred in Nigeria.
Unfortunately, WHO recently suffered a setback in its initiative to eliminate the disease from the planet by 2004. Islamic clerics in northern Nigeria suspended polio immunizations after claiming the vaccine was contaminated with contraceptives and HIV. The suspension contributed to a resurgence of polio in the area, including several cases in neighboring countries. Earlier this year, after two independent labs found no evidence of contamination, Nigeria's president Olusegun Obasanjo pronounced the vaccine safe. Suspicion about the vaccine continues, however, and also has hampered immunization efforts in parts of India.
Faced with these new challenges, the Global Polio Eradication Initiative—a coalition of governments and international health and humanitarian organizations—are redoubling their efforts to achieve a world free of polio.