LIVE POLIO IRUS VACCINES

2. VIROLOGIC AND SEROLOGIC INVESTIGATIONS OF
CHILDREN IMMUNIZED WITH TRIVALENT LIVE
VACCINE FROM A.B. SABIN'S STRAINS
M. K. VOROSHILOVA, V. I. ZHEVANDROVA, E. A. TOLSKAYA,
G. A. KOROLEVA, AND G. P. TARANOVA
DR. VOROSHILOVA
(presenting the paper):
Simultaneous use of three immunologic types
of attenuated strains for mass oral poliomyelitis
immunization allows the vaccination of large
population groups against all three types of
poliovirus within a short time, with most complete
coverage.
It is believed, however, that serologic response
to trivalent vaccine may be lower than that obtained
with individual monovaccines because of
interference between vaccine strains. Therefore,
further accumulation and examination of serological
data is necessary.
The serologic survey of children vaccinated
during the winter of 1959 with trivalent live vaccine
from Sabin strains, in the Estonian and
Lithuanian SSR (Dobrova, Yankevich, Chumakov
et al., 1959), demonstrated sufficiently regular
antibody response to the three poliovirus types in
from 66.7 to 88.6-89.0 per cent of children without
pre-vaccination antibody to one or more types
of poliomyelitis virus. The results varied, however,
in different observations. It would be of
interest to determine factors which affect serologic
response.
In May, June, and July 1959, trivalent live
vaccine was used for mass immunization of children
in the Karaganda and Moscow regions. This
paper presents the results of virologic and serologic
surveys of children vaccinated in the summer
in towns and settlements of the Moscow region
and in three towns of the Karaganda region,
and in Moscow in the winter of 1960.
Surveys consisted of studying the dynamics of
vaccine virus excretion by vaccinees and their contacts
and in determining serological changes. A
number of children was tested for the resistance
of the intestinal tract on additional administration
of vaccine strains one to six months after
primary immunization.
At the same time, we studied multiplication of
vaccine strains in poliomyelitis convalescents who
were treated in a Moscow regional hospital for
poliomyelitis sequelae, in a sanatorium for poliomyelitis
convalescents in Karaganda, and in the
clinic of the Institute for Poliomyelitis Research.
Materials and methods. Children aged two
months to 15 years were immunized orally with
a mixture of monovaccines, prepared at the Institute
for Poliomyelitis Research, from Sabin
attenuated strains of the three poliovirus types.
The vaccine was diluted immediately before use
so that two drops contained 100,000 TCD 50 of
each strain. Practically, of the diluent one ml.
to seven ml. of monovaccine of each type were
added. The vaccine was given to children in a
spoonful of water or tea, followed by the ingestion
of water. The vaccine was fed once or twice
with 1-11/2 month interval.
Before vaccination, stool specimens (one or
two) from all children were tested for enteric
viruses, and blood specimens were tested for
poliomyelitis antibody.
In order to study the dynamics of vaccine virus
excretion after oral immunization with trivalent
live-poliovirus vaccine, important investigations
were carried out in four children's homes: in two
(L. and R.) in the summer of 1959, and in two
(No. 5 and No. 10) in the winter of 1960.
Table 1 presents data on the age and number
of vaccinees, dates of vaccination, and vaccine lot
numbers.
During the first month after vaccination four
to five stool specimens were tested, and during
the second month two to three stool specimens
from each child were tested (Table 2). Stool
suspensions (10 per cent by weight) were prepared
and after centrifugation were treated with
antibiotics.
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