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CSL Pandemic Swine Flu Vaccine Safety in Question


CSL Pandemic Swine Flu Vaccine Safety in Question

Pharmaceutical companies worldwide are rushing to produce their vaccines against the current swine flu pandemic to fulfill the needs of the entire global community, no doubt taking advantage of fast-track approval and immunity from prosecution if serious side effects should come to light [1] (Fast-tracked Swine Flu Vaccine under FireSiS 43) as already found in clinical trials of a live attenuated flu vaccine on children [2] Live Attenuated Swine Influenza Vaccine for Children Safety in QuestionSiS 44).

Now another serious candidate vaccine has appeared. It is produced by an Australian based company CSL Biotherapies. The CSL global seasonal influenza vaccine AFLURIA® is prepared from influenza virus propagated in the fluid of embryos in chicken eggs. Following harvest, the virus is purified in a sucrose density gradient using a continuous flow zonal centrifuge. The purified virus is inactivated with betapropiolactone, and the virus particles are disrupted with the detergent sodium taurodeoxycholate to produce a ‘split virion’. The single-dose formulation is preservative-free; and thimerosal, a mercury derivative, is not used in the manufacturing process for this formulation. The multi-dose formulation, however, contains thimerosal, as a preservative; each 0.5 mL dose contains 24.5 mcg of mercury [3]. The pandemic H1N1 vaccine has been prepared in the same way as the seasonal vaccine. However, CSL also licensed reverse genetic technology (see [2]) from Medimmune company and has indicated that some vaccine may be produced using that method [4].

Inactivation of the virus using beta-propiolactone is a common practice in virus inactivation for vaccines. However, there is some concern about the use of beta propiolactone because it is a potent cancer causing chemical [5]. Beta propiolactone is a direct threat to laboratory workers preparing vaccine. The chemical forms carboxy ethyl adducts on the nucleic acid bases guanine [6] and cytosine [7]. Such modified nucleic acid bases may interfere with the host cell nucleic acid synthesis and/or be incorporated into the DNA of the host cells causing mutations. Cancer incidence has not been studied among those preparing vaccine, nor in those vaccinated using beta propiolactone inactivated viruses.

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