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A COMPARISON OF THE COPENHAGEN AND MADRAS LIQUID
BCG VACCINES |
Kul Bhushan, SS Nair, KT Ganapathy & Vijay Singh:
Indian J TB 1973, 20, 4-9. |
Liquid BCG vaccine produced upto 1955 at the BCG
Laboratory, Guindy, Madras induced low and variable levels of post-vaccination allergy. However, subsequent to improvement in production,
its potency was adjudged as equivalent to Danish BCG vaccine. Later
on, lower levels of post-vaccination allergy in Mass BCG vaccination
campaign and in research studies were observed. A study was planned
to compare the Madras BCG vaccine with Danish vaccine in terms
of the potency of the strains, production efficiency of the laboratory
and stability on storage. This was done by comparing the allergising
capacity and size of vaccination lesions. On a predetermined date
in each of four consecutive months, both laboratories supplied to
the Research Team one week of fresh vaccines from their respective
BCG strains and also fresh vaccine of strains borrowed from the
other laboratory. With these six vaccines every month, in two consecutive
weeks randomly, vaccinations were given to 2,978 tuberculin non-reactors. post-vaccination allergy was elicited 10 weeks later
when size of BCG lesion was also noted. Viable counts on
all vaccines were done by Madras Laboratory.
Though the Indian and Danish BCG vaccines induced
similar levels of allergy, on further analysis it was found that
Madras BCG strain was inferior to the Danish strain and that Madras
Laboratory produced better vaccine than Copenhagen Laboratory. The
vaccine produced from Copenhagen strain in Madras Laboratory induced
the highest level of allergy. The stability of vaccines produced
from Madras strain was found to be unsatisfactory. Results according
to vaccination lesion size and their correlation with tuberculin
reaction more or less confirmed the above findings. They were however
not corroborated in terms of viable counts. Considering that the
inferior quality of Madras BCG strain was due to mutation over time,
seed lots of suitable BCG strain would ensure uniformly potent vaccine
from Madras Laboratory.
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KEY WORDS: BCG VACCINE, POTENCY, DANISH STRAIN,
MADRAS STRAIN. |