Effect of recent prior infection on influenza vaccine immunogenicty
Not Applicable
Completed
- Conditions
- InfluenzaInfection - Studies of infection and infectious agentsInflammatory and Immune System - Normal development and function of the immune systemInflammatory and immune system
- Registration Number
- ACTRN12621000110886
- Lead Sponsor
- The University of Melbourne
- Brief Summary
Not available
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- Completed
- Sex
- All
- Target Recruitment
- 100
Inclusion Criteria
Aged > 18 years; Continual participant in the Ha Nam cohort since 2007 with complete sampling and documentation of A(H3N2) influenza virus infection history
Exclusion Criteria
History of allergic reactions to vaccines
Study & Design
- Study Type
- Interventional
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method Geometric mean ratio of serum hemagglutination inhibition (HI) antibody titres against vaccine virus. The Geometric mean ratio is calculated as the mean of the differences in log 2 titres in post- minus pre-vaccination sera.[Day 14 post-vaccination];Geometric mean titre of hemagglutination inhibition (HI) antibodies against vaccine virus in post-vaccination sera[Day 14 post-vaccination];Proportion who seroconvert, defined as a 4-fold or greater rise in titre of serum HI antibodies against vaccine virus. [Day 14 post vaccination]
- Secondary Outcome Measures
Name Time Method Strain coverage of antibodies induced by vaccination, measured by titrating sera against up to 40 A(H3N2) strains in HI assay. Generalized additive models (GAMs) and lowess models are then used to fit and compare Log2 titre landscapes acoss virus strains arranged temporally or by antigenic distance. Similarly, differences in log2 titres at post- minus pre-vaccination time-points are fitted against temporally or antigenically arranged strains to determine how recent prior A(H3N2) infection affects the production of antibodies that cross-recognize strains circulating before, with and after the vaccine strain.[Pre-vaccination, and days 7, 14, 21 and 280 post-vaccination ];Influenza hemagglutinin reactive B cell frequency and phenotype will be determined by flow cytometry and ELISPOT. The magnitude of the response to vaccination will be determined by subtraction of frequencies in pre-vaccination samples.<br>[Days 7, 14, and 21 post-vaccination. ]