A quick Glimpse…

The Future of Attenuation…

• Genetic engineering techniques provide new methods of attenuation
• Herpes virus vaccine for pigs
• Possible elimination of reversion?

Inactivated Viral or Bacterial Vaccines

• Methods of inactivation include heat or chemical agents
• End result…. Loss of replication ability
• Difficult to inactivate due to potential for denaturation of epitopes
• Dependence on higher order levels of protein structure

Attenuation vs. Inactivation

Attenuation vs. Inactivation

• Attenuation
• Normally require one dosage to induce relatively permanent immunity
• Primarily cell-mediated in nature
• Despite reliance on cell-mediated immunity, increased IgA response
• Inactivation
• Requires multiple boosters
• Emphasis on activating humoral immunity
• However, something very important is missing….

Adjuvants

• Adjuvants are CRITICAL for the use of inactivated vaccines
• Most widely used are aluminum salts (mainly hydroxide or phosphate)
• Effects include liberation of antigen, chemoattraction, and inflammation

ISCOMS

• Immunostimulating Complexes
• Multilmeric presentation of antigen/adjuvant
• Enhanced cell-mediated immune response, delayed-type hypersensitivity, cytotoxic T lymphocyte response, increased Ag expression associated with MHC II

Additional Facts From Dr. David Satcher

• Presented a more social rather than technical view of vaccines
• Barriers to health care include the “7 U’s”
• Uninsured, Under-issued, Under-represented, Uninspired, Untrusting, Uninformed
• Ethical Variations
• Significant Social Costs associated with vaccine-preventable diseases
• $10 billion per year
• 36,000 elderly die yearly from influenza despite availability of vaccine
• Social impetus is needed to lower these figures

Impact of Vaccines on Public Health

• Between 1977 and 1980, smallpox was eradicated in the United States
• Global eradication is currently a major consideration
• Phenomenon of herd immunity
• Measles occurrences at a record low