Question: Why do vaccines sometimes not protect chickens?

• The handling and storage of “live” vaccines is very important.
• Remember that these vaccines contain live viruses or bacteria.
• Very specific temperatures must be adhered to when storing vaccines, or they will be damaged.
• They should not be exposed to direct sunlight or disinfectants, as this can destroy them.
• For each application, make sure every chicken receives a dose of vaccine.
• This is important as any chickens not vaccinated will not be immunised, and this will result in their being susceptible to field challenges.
• Even if they are correctly applied and contain the appropriate antigen to the field pathogens, vaccines do not necessarily provide total protection against disease because there are many variables.
• The farmer should, therefore, follow the correct procedures when developing and implementing a vaccination programme.

Also read:
The difference between live and inactivated vaccines
Livestock production: How vaccines work against diseases
Poultry production: Handling and administering live vaccines
Livestock production: The difference between antibiotics and vaccines

• This article was written by Dr. Mick Versfeld and first appeared in Farming SA