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28
Report of the Medical Officer of Health for 1935.
The age grouping of the persons in whom immunity was
produced is given in Table XII.
Two of the 4,203 persons, who have become protected as
shown by a negative re-Schick test, obtained protection from
an attack of diphtheria which occurred shortly after they had
re-acted positive to the initial test. For this reason no immunising
injections were given, but the two children were tested again
after they had recovered from the attack, and the result of this
re-test was negative.
As it is important to be able to determine, as far as possible,
the time taken to produce immunity and the number of injections
required, a dissection of the protected cases is made in Table
XIII, giving this information. The two cases referred to in the
previous paragraph are not included in the table, which deals
with 4,201 persons.
It will be noticed that the time taken to produce immunity is
shewn to vary very much. The period which elapses between
the last injection of the immunising dose and the re-Schick test
depends to a large extent on the date when the person concerned
attends at the Clinic to be re-tested. Some of it is due,
however, to actual delay in the production of immunity. A
number of the cases included in this Table because the final
re-test was negative have had one or more positive results before
the final negative one was obtained.
An analysis of the information given in Table XIII. brings
out the following points:—
(1) One series of injections was sufficient to produce
immunity in most of the cases—actually, 3,733 out of 4,201
were immunised after the first series.
(2) 420 cases required a second series of injections to
produce the same result.
(3) In a few cases further series had to be given before
immunity was produced.
(4) 2,933 out of 4,201 cases were protected within six
months after receiving the last dose of immunising serum.