抄録
The Cox live attenuated vaccine was given in healthy infants and in poliomyelitis patients. The immunological effect, safety, infection in contacts and replacement of the virulent strain of virus were studied. The following result were obtained.
Administration of all three monovalent vaccine in 6 healthy children ranging in age from 1 month to 14 months resulted in a rise in Type I antibody in 5, Type II in 1 and Type III in all 6. Type I virus was isolated from the stool in 5, Type II in 1 and Type III in 6 children.
In two cases examined, blood picture showed no marked alteration and virus could not be isolated from the blood or spinal fluid.
Autopsy was performed in 2 cases dying of other causes and there were no changes attributable to polio in the spinal cord and virus was not isolated from the organs.
Infection in contacts was investigated. A slowly spreading infection was found in 5 infants, while a fast spreading infection was forund in 6 of 7 children and infection within the family occurred in 8 of 13 subjects.
Vaccine of a viral strain differing from the infective strain was administered in fresh cases of poliomyelitis and the stool examined for the strain excreted. Excretion of the attenuated strain was observed in 7 cases. The finding suggests that the virulent strain is replaced by the attenuated strain and this is significant immunologically as it would be possible to prevent further spread of the virulent strain by giving attenuated virus and also that the live virus vaccine would be a valuable measure at times of poliomyelitis epidemics. Virus excreted in the stool was tested by intraspinal injection in the mouse and it was found that there was some increase in neurotropism following passage in man.
Untoward effects were not found in any of the cases given the live attenuated poliovirus vaccine.
