[Towards the eradication of poliomyelitis: Mexico's achievements and challenges].

Since the strategies to eradicate polio were implemented, the incidence of paralytic polio has dropped dramatically. Four main strategies have greatly contributed: a) High immunization coverage rate with oral polio vaccine (OPV), b) Supplementary immunization activities during the National Immunizations Days c) An effective epidemiological surveillance system for acute flaccid paralysis (AFP) and d) Intensified immunization activities in high risk areas. Three countries remain polio endemic, nevertheless, any country has a potential risk of the virus importation from one of these endemic areas; an accidental release of poliovirus from a research or clinical laboratory, or from having a circulating vaccine-derived poliovirus in the environment.