LIVE POLIO IRUS VACCINES

Further Observations on First Field Trial in Czechoslovakia
509
RESULTS OF INVESTIGATIONS
MADE IN 1959
Our results and conclusions are based on a
confrontation of different facts assembled in the
course of 1959, i.e., the confrontation of the
number of vaccinated individuals with the results
of morbidity investigations, investigations of the
seroimmunity, and repeated investigations of
the spread of polioviruses in different parts of
our country.
year after the third intradermal dose. The table
also shows the number of individuals vaccinated
with the live vaccine in four regions during the
winter of 1958-1959.
1. Results of Morbidity Investigations from
Paralytic Poliomyelitis in 1959. From the figure
summarizing the poliomyelitis morbidity in
Czechoslovakia (Fig. 1), based on the number
of reported cases, it appears that the morbidity
in 1959 was relatively low. The number of cases
25
Slovakia
2 0 Bohemian regions
f15 -
10
5 4_, ........ ...
I/I
i ! , , , !..
1930 1935 1940 1945 1950 1955 year
FIG. 1.
Poliomyelitis in Czechoslovakia per 100,000 population.
The number of individuals vaccinated by different
methods in Czechoslovakia up to 1 July
1959 (before the onset of the usual polio season),
is given in Table 1. One can see from the
table that the relatively high vaccination ratio,
particularly by the intradermal route (twice at
0.125 ml. per dose), is apparent.* Mass vaccination
with a fourth dose of Salk's vaccine in
the Plzeui region (1 ml. of vaccine administered
subcutaneously) was made approximately one
* The change to subcutaneous vaccination with 1
ml. of vaccine in small children over six months of
age was made only at the end of 1958 and manifested
itself particularly during 1959.
was 288 (rate 2.1 per 100,000), i.e., it was
lower than in 1958 when the absolute number
was 302 (rate 2.2 per 100,000). A more detailed
analysis of the morbidity in 1959 (based
on reported cases) reveals certain differences
in the two parts of our State (see Fig. 2); in
the eastern part (Slovakia), not only was a substantial
rise of morbidity recorded, but what is
even more serious, an atypical shift of the morbidity
curve occurred toward the end of the year.
As far as the morbidity of the entire population
of the four regions is concerned, where the live
vaccine has been used (dotted line), we cannot
draw any definite conclusions so far, except that