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Infective Diseases.
21
total of 1,816 for the two years. These numbers are not large
when compared with the child population of the Borough which
was returned as 81,114 at the 1921 Census, but they are an indication
that there is a certain demand for the service.
1,384 persons were given an Initial Schick Test and the
other 432 were given immunising injections without a Schick
Test. Almost all of the latter were young children, under 5
years of age, who were assumed to be susceptible to Diphtheria
on account of their age.
The Initial Schick Test:—An analysis of the results of
the tests performed is given in Table XIII. which shows the
cases divided into age groups and sexes and the result of the
test in each group. The last line of the Table gives the percentage
of the results found to be positive in each group
neglecting those in which the test was not read.
The essential fact brought out by this Table is that 1,014
persons gave a positive result to the initial Schick Test showing
that they were susceptible to Diphtheria. This is 73 per cent.
of the total tested after neglecting 25 cases who failed to attend
to have the test read.
A glance at the last line of the Table will show that the
highest proportion of positive results was obtained at the lowest
age group and that the proportion diminished as age advances.
This is in accordance with the known facts about the Schick
Test. On the other hand, an appreciable number of persons
over 15 years of age showed a positive result and more than
half of them were found to be susceptible. Even allowing for
the fact that most of the adults tested were young this proportion
appears to be high.
Immunisation:—In order to produce immunity three injections
have to be given at weekly intervals. Immunity does
not develop until several months have elapsed after the last injection,
and in order to determine whether this has occurred it