Perspectives on rapid elimination and ultimate global eradication of paralytic poliomyelitis caused by polioviruses

Abstract

Poliomyelitis caused by polioviruses has already been eradicated from industrialized countries of North America, Europe, Asia and Oceania, but the procedures by which this eradication was achieved are not adequate for the poor tropical and subtropical countries. The major challenge now is first to eliminate it rapidly from Asia and Africa where an estimated 250,000 cases and 25,000 deaths currently occur annually. The great progress toward eradication of "wild" polioviruses from poor tropical and subtropical countries in Latin America was achieved not by the procedures still recommended by the WHO Expanded Program on Immunization (EPI) but by the independently organized annual, national days of antipolio vaccination - all based on the use of large armies of well-trained non-professional, community volunteers - first used in Cuba (1962), Brazil (1980), Nicaragua (1981), Dominican Republic (1983), Paraguay (1985), and Mexico (1986). This novel approach, described in some detail in this communication, is recommended for the rapid elimination of wild polioviruses from Asia and Africa, and for ultimate global eradication with the help of a special cadre within the EPI of WHO. The extensive use by the Pan American Health Organization (PAHO) of highly sophisticated regional virus laboratories has led to the recognition that, in areas from which poliomyelitis caused by polioviruses has been largely eliminated, there are thousands of cases of acute flaccid paralysis, previously clinically diagnosed as "probable poliomyelitis", that have no viral etiology, a phenomenon previously reported by Dr. Manuel Ramos Alvarez in Mexico City in 1967.

PIP: Paralytic poliomyelitis caused by the poliovirus has been almost completely eradicated in many countries. This was achieved by a maximal break in the chain of transmission through mass vaccinations. Strategies in the poor subtropical and tropical climates of Asia and Africa where annual estimates of paralysis are 250,000 cases must be adapted to countries characterized as having year-round fecal born infectious agents, including paralyzing polioviruses and other enteric viruses, and inadequate health facilities, poor sanitation and hygiene, and high levels of poverty. A virologic study in Mexico City and the Soviet experience lead to the successful Cuban strategy in 1962 of 2 annual, national days (2 months apart) of mass administration of OPV to all children in a specified age group, regardless of how many doses of OPV already had been received. The implementation by independently organized well-trained nonprofessional community volunteers is provided in detail. It is this strategy that is recommended for a WHO EPI group and Pan American Health Organization effort to eradicate poliomyelitis worldwide. The discussion of the worldwide effort to eradicate smallpox points out that the methods, used for smallpox eradication would be ineffective because poliomyelitis infections are clinically inapparent and vaccination around recognized cases is insufficient to break the chain of transmission. Problems arise due to the misdiagnosis of acute paralytic diseases which pathologically are not poliomyelitis. The distinction between paralytic poliomyelitis caused by polioviruses and paralytic poliomyelitis is made and discussed. The experiences of eradicating paralytic poliomyelitis in economically developed, temperate climate countries and rapid elimination in underdeveloped subtropical and tropical countries is described in some detail. The OPV programs and lessons learned in Cuba (1962), Brazil (1980), the Dominican Republic (1983), Nicaragua (1981), Paraguay (1985), and Mexico (1986) are included. Inadequate mass campaigns which did not work to break the chain of wild polioviruses but reduced the disease level were Columbia (1984), El Salvador (1985), and Turkey (1985). Measures of achievement in Latin American are identified, and recommendations for worldwide eradication are given.