Vaccine Technology

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Vaccine Technology
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Vaccine Technology
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Vaccine Technology
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Vaccine Technology
Strategy Examples of pathogens
targeted Recombinant protein production
Hepatitis B S Ag, pertussis toxin, Lyme outer
surface protein A, CMV gB protein Live
related recombinants Dengue genes in yellow fever
17D, parainfluenza 12 genes in
parainfluenza 3, M. tuberculosis genes in
BCG Alpha virus replicons HIV, Hemorrhagic
Fevers Replication-defective particles HPV,
SARS Naked DNA plasmids HIV and many
others Prime boost using DNA/vectors HIV,
malaria, tuberculosis Reverse vaccinology
Meningococcus B Microarrays for virulence genes
Mainly bacteria Synthetic peptides Cancer, CTL
vaccines Synthetic polysaccharides Hib Reverse
genetics Influenza, parainfluenza, RSV
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Vaccine Technology

• Newer Technology
• Mammalian cell culture live and killed vaccines
• Subunit vaccines
• From serum (HBV) or virus / bacterial disruption
• Made via recombinant DNA technology
• Recombinant vaccine vectors
• DNA vaccines

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Vaccine Technology

• Old Technology
• Grow in animals (vaccinia in calves for smallpox
  rabbit brains for rabies)
• Simple bacterial culture (Cholera vibrio) then
  inactivation
• Grow in eggs (influenza, vaccinia) then inactivate

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Vaccine Technology
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Vaccine Technology
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Vaccine Technology
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Vaccine Technology
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Vaccine Technology
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Vaccine Delivery
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Vaccine Technology
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New problems

• Prospects for control of diseases by vaccination
  are quite bright BUT
• Vaccine supply is insufficient.
• Too few manufacturers
• Regulatory pressures render production more
  difficult.
• New manufacturers in developing countries like
  India, China, Indonesia and Brazil may fill this
  gap.
• Cost of vaccines is also now a problem
• New vaccines require 300 to 800 million to
  develop
• Companies that do RD must recoup costs.
• If vaccines are to be applied broadly throughout
  the world, several circumstances must be
  maintained
• higher price in developed countries,
• recognition by governments that savings justify
  expenditures
• support by donor agencies of vaccine purchases

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• There is a growing demand for vaccine safety.
• As disease recedes, the need for vaccination is
  less obvious
• More people depend on herd immunity
• Herd immunity will fail if too many refuse to be
  vaccinated
• There are real safety problems associated with
  vaccines, like paralysis after oral polio vaccine
  and disseminated infections after BCG
• Older vaccines need to be re-examined to see
  whether safety can be improved
• EG replacement of whole-cell pertussis vaccine
  by acellular pertussis
• replacement of rabies vaccine made in brain by
  vaccine made in cell culture.
• vaccinia will be replaced by further attenuated
  vaccinia and
• Bacille Calmette-Guérin by engineered TB vaccines.

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Risk-benefit ratios
Resistance to risk exposure through vaccine
Risk of disease
Time
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• Zero risk is impossible to attain, and there will
  always be tension between
• the needs of public health and
• the regulatory impulse to guard against even
  remote and theoretical risks.
• As vaccines are key tools for maintenance of
  public health, governments have a major role in
  their dissemination through recommendations and
  purchase.
• It is doubtless more efficient for industry to
  take vaccines from concept to licence, but
  governments should advise about the choice of
  targets for vaccine development and guarantee
  markets for products developed at their request.
• http//www.mcb.uct.ac.za/tutorial/209C/plotkin20v
  accines.pdf