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37
usual intervals. With the development of the manufacture of the
immunizing agent, we changed over to the use of Formol Toxoid
–F.T. The results of the use of T.A.M. appeared to be quite
Successful, but in this matter we are to a very great extent in the
hands of the bacteriologists and those who can carry out experiments
on animals. The length of time necessary in field epidemiology in
a comparatively new product is too long, and we have to adapt our
procedure in accordance with the results of experimental epidemielogy.
The only objection to the use of Formol Toxoid was the
necessity of giving three doses before immunity was established.
Its use was remarkably free from any undesirable or unpleasant
reactions, and the immunity which resulted from its use appeared
to be satisfactory. In 1936, we again changed over to the use of
A.P.T. Alum Precipitated Toxoid, for the simple reason that we
were advised of the potency of two doses. In the case of young
children it is a decided advantage if immunity can be established
with two doses instead of three. As far as we are concerned it has
been found that there is a decided advantage in two doses instead
of rhree; a certain proportion of the children did not turn up for
the third inoculation.
As a test of immunity we are dependent upon the Schick test;
no other method of testing is practicable with the staff at our
disposal. The Schick test is an instrument which has yielded
valuable information in the epidemiology of diphtheria, but its
inherent limitations must be admitted even when higher and more
uniform standards have been perfected. The standards are not
identical, Messrs. Burroughs Wellcome have supplied us with a
four-fold schick toxin and we have used this for the past two years.
It has been pointed out in previous reports that the percentage of
positive reactors is much higher when this stronger toxin is used
than with the ordinary Schick Toxin which is generally used. To
young children a Schick Test is frequently a bigger ordeal than a
single inoculation, and most parents prefer to have their children
re-inoculated when they enter school, than to have them Schick
tested, especially as a certain percentage may prove to be positive
reactors, and require to be re-inoculated after the test.
Since we Commenced immunization, there has been no death
in a fully immunized child. Every year we have given details of
the cases of diphtheria in immunized children. Last year 7 cases
were notified in children who had been immunized. Two of these
on wrongly diagnosed. In both cases there were no clinical signs
on admission to hospital and the results of the swabs taken were
negative. One was admitted on January 12th and discharged on
January 15th and the other was admitted on November 10th and
discharged on November 15th.