LPM 221: Commercial Poultry Production and Hatchery Management (1+1)

INACTIVATED (KILLED) VIRUS VACCINES

• Permanently inactivated by chemical or physical methods
• Contain high concentrations of virus
• Virus does not replicate, larger antigenic mass is required to induce immunity (as opposed to modified vaccines)

Inactivation is achieved by

• Formaldehyde cross links protein and nucleic acid
• Beta propiolactone
• Acetyl ethyleneimine

Adjuvants

• Added to non-replicating vaccines in order to enhance immunogenicity
  • Chemical adjuvants (Aluminum hydroxide, Aluminum phosphate, Calcium phosphate)
  • New lipid adjuvants
  • Liposomes
  • Immune stimulating complexes (ISCOMs)

Advantages of inactivated vaccines

• All antigens are present
• Gives sufficient humoral immunity if boosters given
• No mutation or reversion
• Can be used with immunodeficient birds
• Sometimes better in tropics

Disadvantages of inactivated vaccines

• No replication of pathogen – not induced Cell mediated immunity (CMI)
• Boosters needed
• No local immunity (important)
• Higher cost
• Failure in inactivation and immunization with virulent virus