title: Global polio eradication now hinges on four countries.
mesh_terms: D000293:Adolescent; D000346:Afghanistan / Q000453:epidemiology; D002487:Centers for Disease Control and Prevention, U.S.; D002648:Child; D002675:Child, Preschool; D014943:Global Health; D006801:Humans; D017589:Immunization Programs; D007194:India / Q000453:epidemiology; D009549:Nigeria / Q000453:epidemiology; D010154:Pakistan / Q000453:epidemiology; D011051:Poliomyelitis / Q000453:epidemiology / Q000517:prevention & control*; D023321:Poliovirus Vaccines / Q000008:administration & dosage; D014481:United States
chemical_list: D023321:Poliovirus Vaccines