Expanded programme on immunization. Poliomyelitis outbreak.
D000293:Adolescent; D000328:Adult; D002031:Bulgaria / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003906:Developing Countries; D004196:Disease Outbreaks / Q000517:prevention & control; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D011051:Poliomyelitis / Q000453:epidemiology / Q000517:prevention & control*; D011055:Poliovirus Vaccine, Oral / Q000008:administration & dosage*
D011055:Poliovirus Vaccine, Oral