|ALLERGY PRODUCING CAPACITY OF MADRAS AND DANISH
BCG VACCINES AS SEEN AMONG SCHOOL CHILDREN IN BANGALORE
|Raj Narain, Kul Bhushan & M Subramanian: Indian
J TB 1961, 7, 1-15.
In all, 1,259 students aged 11-19 years from three
boys high school of Bangalore, formed the study group. They were
tuberculin tested with 1 TU RT 23 containing Tween 80. Boys with
a reaction of 13 mm or less to tuberculin test and willing for BCG
vaccination were allocated in 3 groups: (i) to be vaccinated with
Madras vaccine (211), (ii) to be vaccinated with Danish
Vaccine (236), (iii) control with saline injection (231)
(placebo). Strength of Madras and Danish vaccines used was same,
0.075 mg per dose. After 3 months of vaccination, second tuberculin
test with 1 TU RT 23 with Tween 80 was given to 575 boys included
in both the vaccinated groups and in the control group. A follow
up at one year after vaccination was done among 328 boys, who
were again tuberculin tested.
The analysis of data shows that the mean size of
post-vaccination tuberculin test induration among Madras BCG vaccinated
group was 11.8 mm and among Danish BCG vaccinated group, it was
11.9 mm, the standard deviation were 3.8 and 4.5 mm respectively.
The above differences between the 2 vaccinated groups were not-statistically
significant. Similarly, the post-vaccination allergy in the two
BCG vaccinated groups at the end of one year was not-significantly
different. The mean size of the scar produced by two vaccines were
also smaller. The post-vaccination allergy among persons whose pre-vaccination
tuberculin induration was 9 mm or more to 1 TU RT 23 with Tween
80, did not increase by more than 4 mm after vaccination. While
the group whose pre-vaccination tuberculin induration was below
9 mm, had an increase of post-vaccination allergy of a little over
8 mm. It is concluded that the allergy producing capacity of
the Danish and Madras vaccines was not different.
|KEY WORDS: BCG VACCINE, POST-VACCINATION ALLERGY,
MADRAS VACCINE, DANISH VACCINE.
|ALLERGY AFTER BCG VACCINATION
|Kul Bhushan: Proceed 18th Natl TB & Chest Dis
Workers Conf, Bangalore, 1962, 286-89.
In view of the variable and low levels of post-vaccination
allergy elicited in the Indian Mass BCG Campaign vaccinated groups
as observed by WHO and Indian BCG Assessment Teams, some studies
were carried out to investigate some of the factors considered
having influenced the levels of post-vaccination allergy. The
reasons were potency and storage of vaccine, techniques, interval
between vaccination and retesting and tuberculins used. Potency
of the vaccine: Madras vaccine was compared with Danish vaccine.
The retest done at 3 months with 1 TU RT 23 showed 11.8 mm induration
with Danish and 11.9 mm with the Madras vaccine. Test done after
one year with 20 TU induration was 18.3 mm for both the vaccines.
It is reasonable to assume that the vaccine produced at Madras
is as potent as Danish vaccine. Storage of vaccine: A comparison
of post-vaccination allergy in respect of storage of vaccine by
the ICMR Assessment Team and by Mass Campaign Teams was carried
out in five groups of villages in the neighbourhood places where
five BCG teams were working in Tamil Nadu. The non-reactors were
vaccinated randomly by vaccines stored by either team and with the
placebo III group as control. The retest done after 3 months showed
that in all the five groups combined the mean size of indurations
vaccinated with vaccine stored by Assessment Team were more in the
vaccine stored by Mass Campaign Team. The loss of potency was 0.7
mm per week in vaccine stored by Assessment Team and 1.5 mm per
week stored by Mass Campaign Team. Techniques: The above
study was extended to five more groups vaccinated and tested by
the Mass Campaign Team. Assessment Team also vaccinated separate
groups with the same vaccine and tested on the same day. Mean size
induration for groups combined was higher for assessment team but
not significant. So, the techniques do not seem to make much difference.
Interval between vaccination & retesting: Analysis of
data collected on post-vaccination allergy in the groups vaccinated
by the Mass Campaign Teams retesting according to intervals showed
that the mean size induration decreased with the increase in interval
between vaccination and retesting from 1-20 months. Thereafter,
it rose again. These results indicate a tendency for the allergy
after vaccination to wane with passage of time. The rise is presumably
due to super infection or difference in batches of vaccine. In the
third year (not included in this paper) greater proportion of people
had bigger reactions. Besides, tuberculin used for retesting is
also found to give differences in mean size induration. Tuberculin
5 TU RT 22 gave larger reactions than 1 TU RT 23 with tween, the
differences were above 3 mm.
It can be concluded that at present Madras vaccine
is satisfactorily potent, the post-vaccination allergy is influenced
by storage of vaccine, by interval between vaccination and retesting
and type of tuberculin used for eliciting the allergy. Technique
of testing, reading and vaccination may not influence the results.
Under Indian climatic conditions the liquid vaccine should not be
used for more than 2 weeks. There is a need for Freeze-Dried vaccine.
|KEY WORDS: POST-VACCINATION ALLERGY, LIQUID
BCG, FREEZE DIRED BCG, MASS BCG CAMPAIGN.
|ASSESSMENT OF POST-VACCINATION ALLERGY AMONG THOSE
BCG VACCINATED WITHOUT PRE-VACCINATION TUBERCULIN TEST
|Kul Bhushan, SS Nair & KT Ganapathy: Indian
J TB 1970, 17, 18-31.
The conventional methods of assessment of post-vaccination
allergy by doing tuberculin testing among the vaccinated group are
inapplicable in case of BCG vaccination without prior tuberculin
test (Direct BCG). Because of obvious technical and operational
advantages of direct BCG vaccination a search for a method of technical
assessment of BCG vaccination is important. Hence, a study was
carried out by the BCG Assessment Team of National Tuberculosis
Institute in Tumkur district of Mysore state where Mass BCG Campaign
was going on. Four groups of persons aged 0-20 years, each group
belonging to two BCG Technicians area and vaccinated one day prior
to visit of assessment team, were randomly selected. Besides, persons
(0-20 years) from 2 unvaccinated villages of adjacent area were
included as control groups. All persons were registered simultaneously
tuberculin tested with 1 TU RT 23 and 5 TU RT 22 within 24
hours of BCG vaccination (for pre-vaccination allergy) and retested
with tuberculin 5 TU RT 22 at the end of 3 weeks and 3 months (for
post-vaccination allergy). The four vaccine groups were vaccinated
with vaccine batch Nos. 977, 978, 981 and 984 respectively. Classification
of the directly vaccinated persons into previously infected and
non-infected by tuberculin test administered within 24 hours of
vaccination and about 12 weeks later, elicitation of post-vaccination
allergy only among the non-infected, has been considered as the
Reference Test for judging the suitability of other methods of assessment
studied. The main findings are: (1) The Reference Test showed that
the four batches of BCG vaccine used had induced varying levels
of allergy. (2) Assessment based on the mean size of post-vaccination
reactions among 0-4 years age group, which consists predominantly
of previously non-infected persons, showed a different pattern of
differences between the four batches of vaccine as compared to the
Reference Test. Moreover, to get adequate number of children aged
0-4 years, it will be necessary to cover a comparatively large population.
(3) The method of using the mean size of post-vaccination reactions
among those classified as non-infected on the basis of vaccination
reactions of size 0-13 mm at the site of BCG vaccination on the
4th day of vaccination showed results similar to the Reference Test.
But this method has only a marginal operational advantage over the
Reference Test. (4) Using size of induration at the site
of vaccination on 21st day of vaccination did not give the same
results as the Reference Test. Operationally this method would have
been most suitable as it involved only one visit to the group. (5)
Differences between mean size of post-vaccination tuberculin reactions
among directly vaccinated persons and mean size of (natural) allergy
in reactors among neighbouring unvaccinated areas showed the same
results as the Reference Test. This method has the operational advantage
but needs further investigations. (6) Tuberculin testing of all
directly BCG vaccinated persons including the natural reactors about
12 weeks after vaccination compared favourably, with the reference
method, as the tuberculin reactors contributed less than 1 mm over
and above the allergy in the vaccinated non-reactors . This method
would be useful when rate of tuberculin reactors is less than 20%
in 0-20 years age group and their mean size is also less than 20
mm. Operationally, it is a simpler method next only to No.4 above.
Further investigations are considered necessary for final selection
of this or any of the other methods.
|KEY WORDS: BCG, POST-VACCINATION ALLERGY, ASSESSMENT,
DIRECT BCG VACCINATION.