Poliomyelitis: The paradigm of an eliminated disease. Sequelae and challenges to eradication

Abstract

Polio represents one of the most emblematic cases in the history of public health. Its greatest impact occurred during the first half of the 20th century, with devastating epidemic outbreaks that caused half a million cases annually with tens of thousands of deaths, in addition to leaving many survivors permanently paralyzed. The scientific community responded in an exemplary manner by studying polio until they developed two effective vaccines: an inactivated vaccine (Salk, 1955) and an attenuated vaccine (Sabin, 1962). A global response was immediately organized based on international cooperation, well-defined immunization strategies, and epidemiological surveillance. The mass vaccination effort carried out since 1988 through the Global Polio Eradication Initiative (GPEI) managed to reduce cases by 99.9%. Currently, the wild polio virus only persists in Afghanistan and Pakistan, and the GPEI's “Eradication Strategy 2022–2026” has been implemented with the hope of certifying its complete eradication in the coming years. Two significant challenges remain: controlling outbreaks caused by vaccine-derived polioviruses and increasing low immunization coverage in certain regions.