Vaccines and viral antigenic diversity.

Area of Science:

• Virology
• Immunology
• Computational Biology

Background:

• Antigenic diversity in RNA viruses arises from mutation and recombination, leading to variants that evade host immunity.
• Viruses such as influenza, foot and mouth disease (FMD), and bluetongue (BT) exhibit significant antigenic diversity.
• Effective vaccination against these viruses depends on matching vaccine strains to circulating field strains.

Purpose of the Study:

• To review strategies for managing antigenic diversity in viral pathogens.
• To highlight the importance of surveillance and vaccine strain selection for viruses with high diversity.
• To introduce antigenic cartography as a novel computational tool for quantifying antigenic distances.

Main Methods:

• Review of existing surveillance programs for equine influenza, FMD, and BT.
• Description of regulatory frameworks for vaccine strain updates.
• Application of antigenic cartography to analyze viral evolution in relation to vaccine strains.

Main Results:

• Equine influenza has a formal vaccine strain selection scheme and regulatory framework.
• FMD surveillance is extensive, but a formal vaccine strain selection system is lacking.
• Antigenic cartography quantifies antigenic distances, aiding understanding of cross-protection and viral evolution.

Conclusions:

• Effective vaccines against antigenically diverse viruses require methods to measure antigenic distances and understand cross-protection.
• Antigenic cartography is a valuable computational tool applicable to influenza and other diverse pathogens like FMD.
• Harmonized approaches to virus characterization are crucial for developing internationally agreed vaccine matching systems.