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REPORT ON THE WORKING OF THE KING INSTITUTE, GUINDY
which have stopped for four months. These figures as far as they go, point to the
fact that a general four months' cessation would be more beneficial to the vaccina-
tion rates than the shorter two months' period at present in vogue in certain
districts.
Estimation of vaccination rates.
Experience gained during the year has lead to the belief that the present
standard of judging the measure of success obtained in vaccine operations is not
strict enough.
Up to the present the official returns have only taken account of the success
rate. The insertion success rate has not been recorded.
This latter rate, however, is also essential if a true estimate of the value of
a lymph is to be made. Arrangements are being made with the Director of
Public Health for the issue of a revised form upon which vaccination returns will,
in future, be made. This form has been drawn up in such a way that primary,
secondary and revaccinations can all be recorded separately, the success rate and
insertion success rate being recorded for all. three types of vaccination. It is to
be hoped that much more exact information will be the result of this innovation.
Another point which has a most important bearing upon this subject has to
do with the vaccination staff of the Presidency at large.
The success rates obtained with lanoline lymph by the King Institute staff
in the Saidapet range have been shown to be considerably lower than those given
by the Presidency vaccinators with the same lymph. This can only mean that
the standard for a successful vaccination adopted by the vaccination staff is lower
than that of the King Institute. The majority of cases in the districts are veri-
fied sometime after vaccination. It is probable therefore that very small and
doubtful scars have been taken as evidence of successful vaccination. This is a
point of very considerable importance. It has been shown that there is a correla-
tion between the size of the scar area and the immunity conferred by vaccination.
All cases such as those referred to above although registered as successful
vaccinations are in reality inefficiently protected or not protected at all. There
is thus a danger of their being infected if an epidemic should occur. When many
cases of this type are present a position of affairs may arise where smallpox may
be prevalent in an apparently well vaccinated community with a high incidence
amongst the vaccinated. Such a position is very undesirable for it brings
discredit upon vaccination and disturbs the public confidence in this well proved
measure of protection.
All vaccination operations have, as their ultimate aim, the protection of the
community against smallpox. The only measure of this protection is the number
of individuals who have been efficiently vaccinated. It is therefore of vital
importance that the vaccination returns should be accurate for it is by this means
alone that the extent to which the community is protected against smallpox can
be measured. The most reliable method of judging the success of a vaccination
is to inspect the case while the vesicle is still present. The efficiency of the
Presidency vaccination operations could therefore best be tested if the Deputy
Inspectors of Vaccination made a point of seeing as many of their cases as possible
at this stage.
Yield of pulp.
Statement V shows the monthly average yield of pulp per calf for the year.
It is satisfactory to note that there has been a further considerable increase in the
yield, the average for the year being 20.2 grammes as against 14.6 grammes for
the year 1920–21. The number of calves used was thus reduced from 1,360 to
997. This reduction represents a saving under this head of
2,496.
It is probable that the limit in this direction has now been reached and that
the annual average weight of pulp will in future show a certain amount of varia-
tion, sometimes reaching the present year's figure at other times falling below it.
The average weight of pulp per calf at the Belgaum Institute during my visit in
1919 was about 17 grammes. The King Institute has now reached this satisfac-
tory standard with smaller calves and more cannot therefore be expected.
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