smallpox vaccine and vaccination in the intensified ... - libdoc.who.int

11. VACCINATION IN THE INTENSIFIED PROGRAMME 549
Table 1 1.8. Independent testing in 1967 by the WHO International Reference Centre for Smallpox Vaccine
in Bilthoven of production batches intended for use in the eradication programme or in
experimental productiona
Continent
Proposed for use in the eradlcatlon
programme through donation to WHO Experimental production batches
or through bilateral contributions
Nurnber of
Number of Number of
Number of Number of
Nurnber of
producers batches
batches
batches batches
tested unsatisfactoryb
producers
tested unsatisfactorya
Americas I I I 0 0 0
Africa I I 0 5 2 1 19
Asia 2 I I 9 3 6 4
Europe 2 22 12 6 I2 2
Total 6 35 22 14 39 25
a In this and later tables, the designation of resulrr as "satisfactory" or "unsatlsfanory" was based on the following criterla for a
satisfactory product (titres expressed in pock-forming unlts per ml):
lnltial potency: 2 108.0
Heat stablllty, titre after 4 weeks at 37 'C: 3 108.0
Bacterial count (colonies per ml): < 500
Falled to meet WHO requirements In terms of initial potency or heat stablllty.
methods and quality control so that potent,
heat-stable vaccine could be made available to
the global programme.
A number of steps were therefore taken by
the Smallpox Eradication unit to improve the
quality of the vaccine and to ensure an
adequate supply:
(1) organization of a Travelling Seminar
on Vaccine Production in March 1968, which
resulted in the production of a WHO docu-
ment on production methodology;
(2) arrangement of visits to production
laboratories by WHO programme staff and
consultants ;
(3) establishment of a reference vaccine;
(4) production of seed lots of Lister strain
vaccine by the WHO International Reference
Centre for Smallpox Vaccine;
(5) development of a rapid heat-stability
test for the vaccine; and
(6) regular checking of vaccine potency
and heat stability by the WHO reference
centres.
Meeting of Experts (March 1968)
Although the basic principles of vaccine
production and testing had already been
described in two issues of the WHO Technical
Report Series (WHO Study Group on Requirements
for Smallpox Vaccine, 1959 ;
WHO Expert Group on Requirements for
Biological Substances, 1966), the steps in the
production of smallpox vaccine had mostly
been empirically developed. Little specific
information about ~roduction methods had
been published in 'the scientific literature.
Furthermore, the survey had shown that
unsatisfactory batches of vaccine were being
produced in laboratories in developed and
developing countries alike.
WHO usually handled such problems by
arranging for a well-qualified cbnsultant tb
visit and advise the appropriate institutions,
in this case the ~roducers whose vaccine had
been found to be unsatisfactory. However,
since there were then at least 20 producers
supplying vaccine of substandard quality, it
was difficult to recruit consultants who had
the requisite experience and skills in the
technical procedures and production management,
and who would be able to devote the
necessary time to such an operation. These
considerations led the Smallpox Eradication
unit to conclude that a bette;way to improve
vaccine production rapidly would be to prepare
a manual on the production of freezedried
small~ox vaccine that would describe
the simplest possible procedures for all stages
of production and testing of a potent, stable
and safe vaccine.