Calf-Lymph
Vaccine
Dryvax, the stored calf-lymph vaccine manufactured in the
1970’s by Wyeth Laboratories, is freeze dried (lyophilized)
and must be reconstituted before use. This vaccine was produced
by infection of skin of calves using the New York Board of Health
Strain as seed virus.
Before use, the vaccine will be reconstituted to a 1 to 5 dilution
based on recent experimental evidence that this strength of
vaccine is sufficient to ensure almost 100% take rates in the
previously unimmunized. (The 1 to 5 dilution is equivalent to
full strength in terms of take rates.) The diluent contains
50% glycerin and 0.25% phenol. The vaccine is packaged in multiple
dose vials (100 doses) which, when diluted, will yield 500 doses.
The vaccine will be distributed to strategic holding centers
throughout the United States and may be used in 2002 to fulfill
the recommendations of the national Advisory Committee on Immunization
Practice (ACIP) for immunization of certain teams of investigators
and health care workers. Dryvax has been used in the recent
past to immunize laboratory workers.
Dryvax is not licensed in the United States and will be administered
under an Investigational New Drug (IND) protocol of the Food
and Drug Administration. An IND protocol requires an approved
investigatory program, principal investigator(s), approval by
an Institutional Review Board (IRB), adequate informed consent
procedures, and a system for tracking and responding to vaccine-related
adverse events.
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Tissue
Culture Cell Vaccine
As of October 2002, tissue culture cell vaccines are in preparation
by Acambis-Baxter Laboratories. Two cell lines were selected for
propagation of vaccinia virus; the NYCBH strain was selected as
seed virus.
Vero monkey kidney cells and a human fibroblast cell line (MRC5)
were selected as host cells for the preparation of vaccine. Several
lots of both vaccines have been prepared and are undergoing testing
using an IND protocol as described above. It is anticipated that
one of these vaccines will supplant calf-lymph vaccine if a more
extensive vaccination program is implemented.
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