Hemagglutination Inhibition Assay (HAI)

Overview
Used for measuring influenza-specific antibodies that inhibit virus-mediated RBC agglutination.

Principle

• Sera are treated and incubated with influenza virus.

• RBCs are added, and inhibition of agglutination is assessed.

• Titers ≥40 are considered protective (WHO standard).

Applications

• Influenza vaccine immunogenicity studies

• Population-level seroprevalence analysis

• Antibody-based therapy evaluation

Deliverables from MIV
?? HAI titers with protective cutoffs
?? Data presented in tables and graphs
?? Assay reports aligned with WHO protocols