LIVE POLIO IRUS VACCINES

Course of Mass Immunization in USSR with Vaccine from Sabin's Strains 419
mary immunization. For primary immunization
(Type 1 or trivalent mixture), 78,343,300 inoculation
doses have been distributed.
Since a great deal of work connected with
immunization of the population with live poliovirus
vaccine had already been done in many
republics during 1959, it was decided in these
republics (Kazakh, Uzbek, Georgia, Azerbaijan,
Moldavia, Lithuania, Kirghiz, Zajik, Turkmenistan,
and Estonia) to give only two vaccinations
in 1960: first, with Type 1 monovaccine, and second,
with trivalent mixture (Types 1, 2, and 3)
of live vaccine, which will cover the entire population
from two months to 20 years of age.
In RSFSR, Ukrainian, Byelorussian, Latvian,
and Armenian Republics, immunization was carried
out in 1960 with monovaccines given three
times. In some regions of the Ukraine, trivalent
mixture was administered twice. All large-scale
vaccination programs have been realized by
1 June 1960 in 13 out of 15 republics, and in
RSFSR and Ukrainian SSR, they will be completed
by 15-20 June.
After the termination of mass vaccination programs
all over the country, immunization is
scheduled for growing-up infants aged two to
seven months who had not been involved by
vaccinations during winter-spring immunization
campaign.
There are no precise figures available at present
showing the actual numbers of those immunized
with the live vaccine in 1960. But
taking into account the usual losses incident to
the distribution of the vaccine during immunization
(about 15-20 per cent), one may expect that
before 15 June 1960, over 65 million persons in
the USSR (or about 84 per cent of the population
aged up to 20 years), will have completed
vaccinations with three types of live poliovirus
vaccine from Sabin's strains. Consequently, in
less than six months we were able to immunize
the vast majority of susceptible population and
to fulfill over 84 per cent of the annual poliomyelitis
vaccination program. As is well known,
it took more than four years in the U.S.A. to give
two or three shots of Salk vaccine to about 50
million persons (according to data of The National
Foundation as of 31 December 1958).
Undoubtedly, speed and broadness of involvement
with live virus vaccinations greatly exceed
those in vaccination with Salk vaccine. TRDese
factors, in turn, are important in reducing circulation
of wild poliovirus strains. In order to
completely deprive wild poliovirus strains of the
possibility to circulate among the population
regularly, and at the same time to provide uninterrupted
immunization, we are planning in
1961 to carry out the following schedule of live
virus vaccinations which are to involve all children
of 0 to 3 years of age:
First vaccination of newborn children during
the first seven days of life with Type 1 Sabin
vaccine;
Second vaccination between the second and
the third month of life with a mixture of Types 2
and 3 vaccine;
Third vaccination between the fourth and the
sixth month of life with a trivalent mixture of
Types 1, 2, and 3.
Accordingly, the cycle of immunizations will,
as a rule, have been completed by six months
of age. Besides, there will be annual revaccination
of children aged one, two, and three years
with one feeding of trivalent mixture (during
certain times of the year). So there will be annual
vaccination of four groups of children under
three years of age. This will enable the population
to be provided uninterruptedly with immunizing
vaccine strains of poliovirus and to
counteract the dissemination of wild poliovirus
strains.
In addition to supplies necessary to ensure the
fulfillment of internal programs of mass immunization
with live poliovirus vaccine from Sabin's
strains, the Soviet Union furnished, by way of
friendly assistance, vaccines of Types 1, 2, and
3, separately for 2.5 million children in Hungary,
Types 2 and 3 vaccines for 1.5-2 millions in
Czechoslovakia, for 1.5 million children in the
People's Republic of Viet-Nam, and for 2.2
million children in Bulgaria. Small amounts
were given to Albania and China.
Because of the complete support on the part
of medical workers and the entire population, we
have no doubts that the large program envisaged
by us for immunization with live vaccine in 1960
will be realized. Oral immunization with live
poliovirus vaccine in dragée-candy makes it
possible to accomplish mass vaccination of susceptible
population within short periods of time.
And this guarantees radical prevention of poliomyelitis
epidemics.