title: Two countries re-infected with polio, as Nigerian state resumes vaccinations.
mesh_terms: D016701:Guinea / Q000453:epidemiology; D006801:Humans; D017589:Immunization Programs; D008302:Mali / Q000453:epidemiology; D009549:Nigeria; D011051:Poliomyelitis / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D023321:Poliovirus Vaccines / Q000008:administration & dosage*; D014944:World Health Organization
chemical_list: D023321:Poliovirus Vaccines