[Possibility of occurrence of mild spinal forms of poliomyelitis in subjects immunized repeatedly with live poliomyelitis vaccine].

The results of clinical, epidemiological, serological and virological examinations of patients with mild spinal forms of poliomyelitis occurring under conditions of mass immunization with oral live poliomyelitis vaccine are presented. The etiological role of poliomyelitis virus types I and III in these diseases has been established. It has been shown that multiple vaccination does not always prevent diseases but in these cases they are milder. Serological examination of patients and normal subjects suggests inadequacy of seroconversion to poliomyelitis viruses under conditions of mass vaccination of the population against poliomyelitis.