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NOTES ON VACCINATION IN ASSAM FOR THE YEAR 1917-18.
1. Introductory.—I was in charge of the Department throughout the year and
the usual routine of work was followed.
2. Vaccination agencies.—The vaccination of the general population was per-
formed by 805 departmental vaccinators and on tea estates the vaccination work was
done by the garden medical staff. The average number of persons vaccinated by
each vaccinator was 1,047 during the year 1917-18, as compared with 1,080 in the
preceding year.
3. Total number of operations.—The total number of vaccination operations
performed by all agencies during the year 1917-18 was 354,323, as compared with
371,662 in 1916-17, showing a decrease of 16,701 in the primary operations and 578
in re-vaccinations.
The total number of operations as performed by the different agencies is distri-
buted as follows :—
319,566 operations by departmental vaccinators ;
3,270
„
by the staff of dispensaries ;
28,927
„
by the tea garden agencies;
2,479
„
by the Jail and Lunatic Asylum agencies; and
81
„
by railway medical officers.
The variations in the district returns are noted in paragraph 8 of the report.
4. Deaths from small-pox.—The ratio of deaths from small-pox during the year
917 was .59 per mille of population, against .47 in 1916. The highest ratio 2.24
was reported from the district of Cachar, followed by the districts of Garo Hills .98,
Sibsagar .96, Goalpara .79 and Kamrup .74. The rate for the Cachar district was
the highest since 1903.
5. Dispensary vaccination.—Three thousand two hundred and seventy persons
were vaccinated at dispensaries during the year 1917-1S, as compared with 3,712 in
1916-17, showing a decrease of 442 cases. As remarked in the previous reports,
vaccination by the dispensary staff is not pressed, and only those who visit dispen-
saries for this purpose are vaccinated there.
6. Percentage of successful operalions.—The percentage of success in known cases
was for all agencies 93.90 in primary operations and 67.05 in re-vaccinations during
the year under report, as compared with 97.73 and 69.10, respectively, in the preced-
ing year.
The fall in the success rate is due to the issue in October of vaccine which had
been in cold storage for periods approximating to six months, and had deteriorated
somewhat in potency. These vaccines had been proved to be free from extraneous
organisms and had been tested in Shillong to ascertain their potency. In spite of
giving good results in the hills, the potency of the lymph was inadequate to resist the
adverse effect of high temperatures in the plains in October, and the result was that a
large number of insertions failed. To this result the unsatisfactory working of the cold
storage plant contributed by exposing the stored lymph to a higher temperature than
that at which it should be stored. For next season's work, lymphs of more recent origin
will be issued for October work and precautions to prevent delay in use will be more
stringently enjoined. A more even temperature in the cold storage room is now
being maintained, but it is probable that three months will prove to be the maximum
period of storage permissible at the temperatures attainable with the present plant,
and that we shall have to regulate our issues accordingly. Against these failures
must be set on the credit side of the account the gratifying absence of septic arms,
or excessive reaction, as the result of insertions made with tlie stored lymph.
7. Different methods of vaccination.—As in previous years, all vaccination ope-
rations were performed with glycerinated lymph manufactured in the Vaccine Depôt
at Shillong.
8. Vaccination work in different districts.—Compared with the preceding year,
the number of persons vaccinated by all agencies in the province during the year
1917-18 showed a decrease of 17,339 cases. The districts which showed an increase
were Manipur State (+12,929), Kamrup (+9,264), and Lakhimpur ( + 8,282). The
increase in the district of Kamrup is due to an increase in the staff of vaccinators