Bacterins:
Bacterins are the vaccines containing killed bacteria.They are usually produced by chemical killing of the infectious agent, with the aim to preserve bacterial structures expressing epitopes important in eliciting a protective immune response. This is usually done with formaldehyde and adjuvant like aluminum hydroxide or alum is added to increase its immunogenicity.
Autogenous vaccines are prepared using the organism from the infected animal itself or from other infected animals in the same farm after inactivation with formaldehyde and found successful to control diseases. For example, the fowl cholera vaccine.
Bacterins and toxoids administered parenterally are not as effective against intracellular pathogens.
Inactivated vaccine
Advantages:
- Easy to prepare
- No reversion to virulence
Disadvantages:
- Immunity is short lasting (usually less than six months)