title: Immune response to influenza vaccination in community-dwelling Chinese elderly persons.
abstract: We investigated the immune antibody response to influenza vaccine in community-dwelling Chinese elderly persons in Hong Kong. One hundred and twenty-eight subjects were recruited in a single-blind, randomized, and placebo-controlled trial. There was no significant baseline difference between the vaccine and placebo groups regarding the seroprotection rates (PR) (haemagglutination inhibition [HI] titre>or=1:40) and geometric mean titres (GMT) of the HI antibody titers. The PR, GMTs and serological response rates increased significantly in the vaccinated versus placebo groups in A-H1N1 at both weeks 4 and month 6. The GMTs and serological response rates but not the PR for A-H3N2 and influenza B increased significantly in vaccinated versus placebo group at week 4 and month 6 post-vaccination. Multivariate logistic regression analyses of the seroconversion rate for A-H3N2 within the vaccinated group showed that gender, coronary heart disease and the serum albumin level were significant predictors (p=0.018, 0.009 and 0.025, respectively). Influenza vaccination provoked a protective HI antibody response in community-living Chinese elderly persons. The mean number of unplanned hospital admissions per subject over 6 months was significantly lower in the vaccinated than in the placebo groups. Hospitalized elderly persons had poorer nutrition, 4-week post-immunization HI antibody titres and lower mini-mental state examination (MMSE) score than non-hospitalized elderly persons. Logistic regression analyses showed that chronic obstructive airway disease significantly increased the risk of hospitalization while the serum albumin level and 4-week A-H3N2 PR (HI>or=40) were independent predictors of a decreased risk of hospitalizations.
authors.affiliation: Department of Medicine, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Hong Kong.
authors.forename: S L
authors.initials: SL
authors.lastname: Hui
authors.forename: L W
authors.initials: LW
authors.lastname: Chu
authors.forename: J S M
authors.initials: JS
authors.lastname: Peiris
authors.forename: K H
authors.initials: KH
authors.lastname: Chan
authors.forename: D
authors.initials: D
authors.lastname: Chu
authors.forename: W
authors.initials: W
authors.lastname: Tsui
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood*; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006723:Hong Kong; D006801:Humans; D007115:Immunization Schedule; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D008297:Male; D012111:Residence Characteristics; D014611:Vaccination
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines