Table 1.

Factors involved in the design, development and implementation of poultry vaccines.

Type of Bird

Species (chicken, duck, turkey) Sector & Lifespan Broiler: 5–7 weeks Layers: 1–3 years Breeders: 5–7 years

Nature of Disease

Extent of spread (episodes, outbreaks, enzootic, epizootic, panzootic, zoonotic, reverse zoonotic) Type of pathogen (viral, bacterial, fungal, parasitic)

Factors Affecting the Vaccine Response

Age and status of immune system at the time of vaccination Presence of maternally derived antibodies (MDA) Vaccine storage preparation and administration Duration of immunity Antigenic distance between field virus and the vaccine Immunogenicity of vaccine strain Route of vaccination Intervals and interference between vaccines Immunosuppression Stress, mycotoxins, vaccine induced immunosuppression Cost effective follow-up; differentiating the infected from vaccinated animal (DIVA) strategy

Types of Vaccines

Inactivated whole virus Live virus vaccines Attenuated (by traditional serial passaging in embryonated eggs or tissue culture) Reverse genetics Nucleic acid based Recombinant protein subunit, virus like particles (VLPs) Viral vectored Monovalent, bivalent, trivalent or multivalent/chimeric Immune complex

Vaccine Application (Routes, Number and Frequency of Doses)

Mass application (spray or drinking water) Individual application (in ovo, eye drop, intranasal, subcutaneous, intramuscular, wing web) Single dose, boosters, multiple doses