Concerns about the high perceived costs of eradicating the relatively low number of polio cases worldwide have led to recent suggestions that it is time to shift from a goal of eradication to control-abandoning eradication and allowing wild poliovirus to continue to circulate, which proponents of control believe can sustain the low number of cases.
In a new study, researchers from the Harvard School of Public Health (HSPH) analyzed the costs and health outcomes of control and eradication options. They found that the relatively high short-term costs of global polio eradication will ultimately be much lower than the long-term financial and human health costs required to control polio forever. The study appears online April 11 and in the April 21, 2007 print issue of The Lancet.
Poliomyelitis, which mainly affects children, is a highly infectious viral disease that can cause inflammation of motor neurons of the brainstem and spinal cord and lead to paralysis. Although successfully eliminated in the U.S. and most of the world through the use of poliovirus vaccines, endemic wild polioviruses still continue to circulate in some countries (notably in parts of India, Nigeria, Pakistan and Afghanistan). Since 1988, the Global Polio Eradication Initiative has reduced the global incidence of poliomyelitis by 99%, at a cost of more than $4 billion.
Kimberly Thompson, Associate Professor of Risk Analysis and Decision Science at HSPH, and Radboud Duintjer Tebbens, a research associate at HSPH, used a mathematical model to demonstrate the importance of maintaining and increasing the immunization intensity in currently endemic areas. Immunization intensity is an indication of the level of vaccination effort aimed at increasing population immunity. The authors suggest that even a relatively small decrease in intensity of immunization could lead to relatively large outbreaks. They emphasized that the world cannot let up in its vaccination efforts for polio, at least until eradication has been achieved.