The studies carried out through the organization of the Japan Live Poliovaccine Research Commission in 1961 and 1962 have provided data necessary for planning and prosecution of the vaccination program. The results will be reported in detail in the following papers. To facilitate the understanding each of the studies, general summary of the studies is given as follows:
It was amply confirmed that Sabin live oral poliovaccine has excellent immunogenicity and is quite safe. The vaccine employed in these studies was shown to have a minimal neurovirulence in monkeys as Sabin prescribed. No significant adverse clinical reactions were observed in vaccinees who were carefully observed. The vaccine viruses proliferated in the intestinal tract in a high percentage of vaccinees and a marked production of neutralizing antibodies against each of the three types of poliovirus was induced. Mass inoculation in the face of epidemic accomplished a dramatic decline of cases within a short period of time. Extremely rare cases with possible association with the vaccine were found among clinical cases occurring following the vaccination. In those cases the possibility of etiologic association of the vaccine virus could be neither denied nor con-firmed. It should be noted that the use of the vaccine was found to be very convenient and practical from the view point of public health administration.
Based on the results obtained by the two-year activity of the commission and the subsequent studies on various aspects of the vaccination, a routine vaccination program with live oral poliovaccine as well as the surveillance system of poliomyelitis cases were established, and the data so far accumulated indicate that eradication of poliomyelitis from this country seems very promising.

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Monovalent vaccine was fed to about 3, 000 children in the order of types 1, 3, 2 at 4week intervals. The results obtained confirm the effectiveness and the safety of the vaccine. Vaccinees demonstrated excellent antibody response to each type of vaccine. Heterotypic antibody response was shown in some vaccinees. Vaccine viruses readily spread to children coming in contact with vaccinees, resulting in a high incidence of seroconversion almost comparable to that obtained among vaccinees, although the viruses spread more readily among children in nurseries than among home dwelling children. None of the vaccinees developed any serious illness and no evidence was found to prove that any of the symptoms observed in some vaccinees was attributable to the vaccine virus. Clinical observation of the contacts gave no evidence for untoward clinical reaction. Vaccine viruses were readily isolated from stools of the vaccinees and contacts for several weeks. Concurrent infection of the intestinal tract with non-polio enteroviruses was shown to exert significant inhibitory effect on infection of the vaccine viruses and hence on antibody response. Pre-existing antibodies, heterotypic or homotypic, reduced the rate of virus excretion after vaccination, but did not significantly affect antibody response.

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Histopathological changes termed by us as “carbohydrate-food type degeneration” developed in the liver of mice when fed for a short period on semisynthetic diets containing rice as the main carbohydrate source even though the diet was supplemented with 23% casein.
When luteoskyrin, a toxic pigment from P. islandicum Sopp was added to these diets, necrosis developed in the liver resulting in tumor formation in the tissues adjacent to these necrotic lesions. The acid soluble sulfer contents in the liver increased in association with the occurrence of degeneration of the liver. The change may be an expression of abnormal metabolism in the liver.

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