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24 Report of the Medical Officer of Health for 1932.
subsequent history of these 3,297 persons is given in the following
statement:—
No. who were immunised and found to be
Protected as shown by a Negative
re-Schick Test 2199
No. who received a course of injections but
are not yet protected as the re-Schick
Test is still positive 152
No. who received injections, the value of which
is not known as they have not attended to
be re-tested 887
Schick positive cases who were not injected 59
Total number of Susceptibles 3297
The age grouping of these protected persons is given in Table
XIV.
The time taken for immunity to be produced and the number
of injections of the immunising substance required to produce
it are given in some detail in Table XV. This table shows that
most of the persons who were immunised—viz. 1,976 out of the
2,199—became negative after one series of injections, while the
remaining 223 required further injections to produce the same
result. The number who were found to be immunised after one
or two injections is now 168. This number has increased from
21 a year ago and is due to the more extensive use, in the year
under review, of the floccular immunising preparation which only
requires two injections, as stated above.
It will be noticed from Table XV. that the time taken to produce
immunity is shewn to vary very much. The time 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, however, due to the actual delay in the production of
immunity. A number of the cases shewn in this Table which have
given final negative re-tests have had one or more positive results
before the final negative one is obtained.