Poliomyelitis in the Americas, 1969-1984.

PIP: The Expanded Program on Immunization (EPI) has made major advances since it was initiated in the Americas in 1977. Immunization coverage approximately doubled between 1977-84, rising from 25-30% to over 60% of the children at risk. Consequently, the incidence of the 6 EPI diseases (measles, poliomyelitis, tuberculosis, diphtheria, tetanus, and pertussis) has been greatly reduced. These achievements have been particularly marked in the case of polio. From 1969 through 1984, a total of 53,251 poliomyelitis cases were reported in the Americas. In the early years of this period, an average of 4274 cases were reported annually. Between 1981-83, the average number of cases reported per year had dropped to 1115. By 1984 only 525 cases of polio were reported in the Americas. The downward trend is clearly evident, even though improved reporting systems in recent years have resulted in larger proportions of existing cases coming to the attention of the public health authorities. All subregions in the Americas have shown a decrease in reported cases since the EPI was launched in 1977. Almost all countries have made notable progress in bringing polio under control. Between 1975-84, there was a 10-fold decrease in the number of reported polio cases, and the number of countries in the Americas reporting cases dropped from 19 to 11. In 1984 the reported incidence for the Region dropped below the goal set for 1971 in the 10-year health plan for the Americas: less than 0.1 cases/100,000 population. 26 countries had maintained incidence below this level for at least 5 years by 1984. The high degree of polio control already achieved in the Americas can be credited primarily to steadily increasing vaccination coverage of the target populations. The proportion of children under 1 year in the Americas who have received 3 doses of polio vaccine increased from about 34% in 1978 to 78% in 1984. The use of special immunization tactics has contributed significantly to the increased vaccine coverage and decreased incidence of paralytic polio. In the future, success will be measured by the absence of any cases of the disease due to wild poliovirus. The high vaccination coverages already achieved in the Americas make feasible the new goal to reduce the number of cases in the Region to zero.^ieng