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way as vaccination is suitable for protection against Smallpox.
Statistics show that where immunisation is done on a large scale
the death rate and case rate of Diphtheria have dropped in a
striking manner.
Immunisation is being carried on in many cities and towns in
this country but it is not yet general. In some American and
Canadian districts very striking results are shown but there are
many difficulties arising with regard to statistical figures and how
we interpret them.
Diphtheria is a disease which is periodic and it might be that
a decrease in the number of cases following an immunisation
campaign, was due to natural causes.
Richmond has been fortunately free from the disease except in
periodic years. In districts is which the disease is more or less
endemic there is a certain natural immunity developed and the
cases seen are not so serious as those which occur in a district
which is comparatively free from the disease for a few years.
Methods Employed.
Immunisation is obtained by the injection under the skin of
various toxoid-antitoxin mixtures. The injections are three in
number at intervals of a week or ten days.
After an interval of three or more months the persons
immunised as above should have a further Schick test in order to
see that they are completely immune.
If not, a further injection of toxoid-antitoxin mixture is
required. (Probably about ten per cent, will require further
injections).
In some districts, in order to save time and probably also
money, the initial and final Schick tests have not been carried out.
Only the immunisation injections have been given to all without
finding out whether they were immune or not. The Ministry of
Health is of opinion that both the initial and the final Schick tests
should be carried out.