Local and national effects of mass polio immunization programs.
D006801:Humans; D017589:Immunization Programs; D032541:Mass Vaccination; D011051:Poliomyelitis; D011055:Poliovirus Vaccine, Oral; D023321:Poliovirus Vaccines
D011055:Poliovirus Vaccine, Oral; D023321:Poliovirus Vaccines
POLIOVIRUS VACCINE, ORAL