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Infective Diseases.
21
children, under five 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 1,826
persons gave a positive result to the initial Schick Test showing
that they were susceptible to Diphtheria. This is 72 per cent.
A glance at the last line of the Table will show that the
highest proportion of positive results was obtained in the lowest
age group and that the proportion diminished as age advanced.
This is in accordance with the known facts about the Schick
Test. Of the small number of adults who were tested 50 per cent,
gave a positive result.
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
is essential for a further test—known as the Re-Schick Test—
to be performed. No person can be said to have been immunised
successfully until the re-test gives a negative result. Unfortunately
the exact period required to produce immunity varies
considerably and it is not possible to give an assurance that it
will take a certain time. After the last of the three immunising
injections has been given, parents are advised to bring their
children for the re-test in about four to six months and many of
them come about that time. A considerable proportion, however,
fail to attend for the re-test and some fail to complete the
course of injections.
The number of persons attending the Clinics who required
immunisation was 2,647. This number is made up of the 1,826
who were found to be Schick positive after the initial test, and the
821, who were assumed to be susceptible without a test. The