For many years polio was thought to be a disease mainly of wealthier nations. Then in the 1960s and ‘70s more extensive surveys revealed that the disease was much more common in developing countries. The astonishing success of the Salk (injectable) and Sabin (oral) vaccines has now entirely eliminated polio from the Western Hemisphere. However, in spite of an intensive worldwide campaign, and the expenditure of eight billion dollars, pockets of disease from virus types I and III, (Type II has been completely eliminated), have occurred in many parts of Asia and Africa. Over the past several years, cases and mini-epidemics have occurred in more countries, and in greater numbers. The reasons for the failure of the Polio Eradication Campaign failure are manifold: India blames their failure on the inadequacy of oral vaccine, along with overcrowding, poor sanitation and diarrheal disease.. Nigeria had an inadequate public health infrastructure, and until recently, a lack of political will. A new problem has also surfaced, the emergence of Sabin vaccine derived viruses that have reverted toward increased virulence and are causing paralytic polio in several locations. Although currently occurring only as isolated cases, the concern is that these viruses will continue to mutate, and eventually cause more widespread and more virulent disease.
Critics have spoken out about whether the relatively huge cost of continuing the active campaign is justified, stating that the massive expenditures of billions of dollars for an eradication campaign aimed at a single disease would be better spent on integrated (read community based) programs aimed at control of a broader spectrum of global health problems and the buildup of local health systems.
Meanwhile as health care volunteers, we need to be aware of the continuing presence of polio in those affected countries in Asia and Africa, and also be aware of the continuing need to stay up to date on our polio vaccination as we travel to these at risk countries.
Ref: Modlin, J. F. The Bumpy Road to Polio Eradication: NEJM 362: 2346, June 24, 2010.
Submitted by Roger Boe MD.