[Poliomyelitis vaccination: politics, problems and people. An unfinished story].

The history of poliomyelitis (polio) vaccination is both complex and fascinating. This article focuses on two distinct, but related, aspects of this history: the discovery and development of the original polio vaccines in the U.S. and the development of the first polio vaccination campaigns in Spain. The epidemiological situation in both countries and the development of vaccines carried out in the United States are analyzed: Jonas Salk's IPV vaccine and Albert Sabin's OPV vaccine. The Spanish response to the possibility of implementing vaccination was slower and late. For different reasons, the health authorities were not aware or did not want to be aware of the epidemiological reality: polio reached its period of highest incidence and mortality in Spain between 1950 and 1963. The IPV vaccine was available in Spain since October 1957 and in 1958, the General Directorate of Health (Dirección General de Sanidad) began a vaccination program with IPV vaccine. In 1963, in the absence of a single campaign, due to conflicts of competence, two simultaneous mass immunization campaigns against polio were organized and developed: a campaign led by the Compulsory Health Insurance (Seguro Obligatorio de Enfermedad), which used the Salk injectable vaccine (IPV), and another campaign by the General Directorate of Health, which used the Sabin oral vaccine (OPV). Heading these two campaigns, it is worth highlighting two people, Juan Bosch Marín and Florencio Pérez Gallardo, protagonists of a scientific confrontation regarding the benefits and usefulness of each of the two vaccines available at the time. The fight against polio encompasses decades of commitment by hundreds of thousands of people to immunization, surveillance, financing, and many other activities around the world. Despite the health gains made through efforts to eradicate polio, which have involved the elimination of wild polioviruses from all but one WHO region, and the global eradication of two of the three wild poliovirus serotypes, we cannot and should not underestimate the challenges that still lie ahead. The goal of eradicating polio is now set for 2026.