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74
DIPHTHERIA IMMUNISATION.
There has been a great deal of discussion in
recent years concerning the advantages of obtaining
artificial immunity from Diphtheria by injections of
toxin-anti-toxin and other preparations. The main
grounds for this propaganda are the dangers and
prevalence of Diphtheria. As a preliminary therefore
to any serious consideration of a scheme of immunisation,
one requires a fairly complete knowledge of the
local incidence of and mortality from this disease.
With this object, Mr. Lloyd has carried out a very
exhaustive analysis of our statistics on these subjects
relative to the past 34 years. The full result of this
enquiry would be too detailed and lengthy for
submission in this report, but the following summary
will show the main conclusions to which it tends :
Case Rate
per 1,000 popn
Death Rate
per 1,000 popn.
Case Mortality
Rate
per 100 cases
1901-1905 2.6 0.3111.5
1906-1910 1.8 0.16 9.3
1911-1915 2.5 0.18 7.7
1916-1920 4.0 0.30 7.3
1921-1925 4.5 0.23 5.1
1926-1930 4.0 0.11 2.7
1931-1934 3.5 0.10 2.9
It will be seen that while the mortality has very
substantially declined, the case rate shows some
increase. With regard to the latter, however, it
should be borne in mind that this is calculated on the
number of " notified " cases and is not altogether a
reliable statement of the number of cases of clinical
Diphtheria which occurred in the year. In 1933, for
instance, I received notice from the fever hospitals
that in 82 cases or 16.8% of the total, the diagnosis
of Diphtheria was found to be incorrect. In 1934 this
happened in 14.9% of the cases. In 1901 and 1902,
a similar correction was made in 7.8% and 8.1% of the
cases. I have no means of knowing whether these
corrections are complete or not, but it seems obvious