Virology 7 and 8: Vaccines

Natural infection

For acute non-lethal infections, what is the best protection achieved from?

Immunocompetent host

What do vaccines require in order to be effective?

Prevent clinical signs and transmission

Goal of vaccines

Two weeks

How long does it take for protection to occur after vaccination?

• Stable; no cold chain (refrigeration) requirement; no reversion to virulence

• No shedding of vaccine virus (modified live vaccines)

• Provide sterilizing immunity (no virus infection)

• Deliver protection in a single dose (aids with compliance)

• Contain a DIVA marker and companion diagnostic test

• Cost-effective

• Resistant to pre-existing blocking antibody

• Safe– can be used at any time during the animal’s life (neonates, adults, pregnancy)

Ideal properties of a vaccine

Plowright vaccine

The vaccine gold standard that helped eradicate the rinderpest virus in cattle

• Live-attenuated vaccine that delivers lifelong immunity in a single dose

• Genetically stable with no reversion to virulence

• Highly protective– close to sterilizing immunity

• No vaccine virus shedding

• Temperature-stable (no cold chain)

• Provides an overview of vaccine safety and efficacy

• Claims are the result of several years of research

• Claims for two similar vaccines or products may be different

• Claim language may be nuanced; never, should, could, can be used, may never be used, must never be used, etc.

• Protection from liability

• Off-label use of vaccine

• Recommended or approved use may change

Important things about label claims/product inserts