The results are presented of personal observations carried out over а period of two and а half years on а group of 39 children aged 6-7 years, which underwent immunization in 1959 and thereafter were twice reimmunized (1961 and 1962) with live poliovaccine, prepared from the А. Sebln strains.
During the mass immunization with live antipoliomyelitic vaccine only 27 children were immunized of the total 39; the remaining 12 children formed the control group (they were living in close proximity with the immunized) which would render possble the following up of the widespreading of the live vaccine virus bу way of direct contact.
Prior to immunization 13 cases of the total number investigated had nо antibodies at all towards type I, 3 - towards type II and 6 - towards type III of the poliovirus.
Following the immunization with live vaccine, all immunized as well as the children in contact with them formed antibodies against all three polioviral types. Only two children did not raise antibodies against polioviral type III. These antibodies were preserved for more than оnе year though with somewhat lowered titer.
Before the 1961 immunization оnlу two children didn't form antibodies one against II and the other against III polioviral type. The raising of antibodies against type III in one of the children, which was not noted after the 1959 immunization, is very рrоbblу due to the contact with the immunized children.
The first immunization in 1961 accounted for the formation of antibodies in all the children in а higher titer as compared to the 1959 immunization. Besides that, these antibodies were preserved in relatively sufficiently high level so that, prior to the second reimmunization in 1962, only one child was free of antibodies against polioviral type I. The immunological response to the second reimmunization was much more favourable. It is further emphasized, that all the children raised antibodies, and only one of them presented antibody in titer 1:8, all the remaining having antibodies in higher titers.
Whereas 65 % of the children examined prior to immunization had antibodies in titer l:8 and only 4,6 %-in titer 1:64, subsequent to the second reimmunization the figures were 0, 9 % аnd 53 % respectively.
The tendency is pointed out towards а continuous increase in the average titers of the antipoliomyelitic antibodies following each reimmunization and their preservation at а higher level, as well as towards an increase in the number of children with high-titer antibodies.
Against the background of their personal investigations, the authors draw the inference to the effect that the problem for the intervals and frequency of reimmunizations of children with the live antipoliomyelitic vaccine couldn't bе conside red as definitely solved.
Величков, В., Митов, Г., Стефанова, 3., Нинов, Н. : Научни трудове на ВМИ - София, т. XII, вип. 1, с. 85-90, 1962.
Величков, В., Митов, Г., Стефанов, 3., Нинов, Н. : Сп. Хигиена, кн. 2, с. 37-42, 1961.
Величков, В., Стефанова, 3., Митов, Г., Нинов, Н. : Бюлетин на Научно-изследователския институт по неврология и психиатрия, бр. 4, 1962.
Митов, Г., Нинов, Н. : Сп. Хигиена, кн. 4, с. 47-51, 1961.
Рангелова, Ст., Кръстев, Т., Иванов, Н. : Сп. Хигиена, кн. 2, с. 43-46, 1961.
Стефанова, 3., Величков, В., Митов, Г., Нинов, Н. : Трудове на Научно-изследователския институт по неврология и психиатрия, т. VII, с. 13-18, 1961.
Меlniсk, J. L., Орtоn, Е. М.: Bull. Wld Hlth Org. 14, 129-146, 1956.
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