title: Successes and challenges in global immunization efforts.
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Hay
mesh_terms: D002648:Child; D002675:Child, Preschool; D014943:Global Health; D006801:Humans; D007114:Immunization; D007223:Infant; D038622:Internationality; D032541:Mass Vaccination / Q000458:organization & administration*; D014944:World Health Organization